JavaScript, Node, Deno V3.1.X

Introduction

SDK overview

Welcome to the Flagship JavaScript / TypeScript / NodeJS & Deno SDK documentation!

The following article will guide you through the steps to get Flagship up and running on your JavaScript environment (client-side or server-side) using our library with preconfigured methods to implement the Decision API or Bucketing Mode.

SDK features

That SDK version helps you :

Prerequisites

NodeJSDeno
- Your server/device must have an access to the internet.
- Node.js: version 6.0.0 or later
- NPM: version 3.0.0 or later
- Your server/device must have an access to the internet.
- Deno: 1.10.3 or later

Good to know

NodeJSDeno
- Github repository: https://github.com/flagship-io/flagship-ts-sdk
- Gzipped size: ~18.9kB
- SDK runs on both Client and Server-side
- Typescript code supported
- Github repository: https://github.com/flagship-io/flagship-ts-sdk
- Deno land: https://deno.land/x/flagship_io_js_sdk

πŸ“˜

Javascript SDK - Engine compatibility

Our Javascript SDK is compatible with :

  • V8 Engine
  • Node.js runtime
  • Deno

Getting Started

Installation

NodeJS

The SDK can be added as dependency via NPM or YARN

yarn add @flagship.io/js-sdk
npm install @flagship.io/js-sdk

Deno

Deno supports 2 methods:

  • URLs for dependency management, so you just need to add the deno.land URL
import { Flagship } from "https://deno.land/x/flagship_io_js_sdk/mod.ts";
{
   "imports": {
      "@flagship.io/js-sdk": "https://deno.land/x/flagship_io_js_sdk/mod.ts"
   }
}
JavaScript & NodeJSDeno
To initialize and start the SDK, import the Flagship class from @flagship.io/js-sdk package then simply call the static function start. It should be better to call this function just once in the most appropriate location for your application.To initialize and start the SDK, import the Flagship class from flagship deno land repos then simply call the static function start. It should be better to call this function just once in the most appropriate location for your application.

Initialization

The first step to use the SDK is to create an instance of Flagship that defines your Flagship account and targeted environment.
Here's the simplest way to initialize Flagship, including the import :

import { Flagship } from "@flagship.io/js-sdk";

Flagship.start("<ENV_ID>", "<API_KEY>");

// or

const fsInstance = Flagship.start("<ENV_ID>", "<API_KEY>");
import { Flagship } from "https://deno.land/x/flagship_io_js_sdk/mod.ts";

Flagship.start("<ENV_ID>", "<API_KEY>");

// or

const fsInstance = Flagship.start("<ENV_ID>", "<API_KEY>");

start function

Start the flagship SDK and return the Flagship instance.

  • static start (envId: string, apiKey: string, config?: IFlagshipConfig): Flagship
ArgumentsTypeRequiredDescription
envIdStringRequiredEnvironment id provided by Flagship.
apiKeyStringRequiredApi authentication key provided by Flagship.
configObjectOptionalCustom flagship configuration. see configuration attribute

Advanced Configuration

Here are all available settings you can set on the SDK.

Those settings can be setup only at the start function.

Here's the full pure example of usage :

import { Flagship, DecisionMode, LogLevel, CacheStrategy } from "@flagship.io/js-sdk";

Flagship.start("<ENV_ID>", "<API_KEY>", {
  decisionMode: DecisionMode.BUCKETING,
  fetchNow: false,
  timeout: 10,
  enableClientCache: true,
  logLevel: LogLevel.CRITICAL,
  logManager: sentryMiddleware,
  decisionApiUrl: 'https://example.com',
  pollingInterval: 100,
  hitDeduplicationTime: 0,
  trackingMangerConfig: {
      cacheStrategy: CacheStrategy.PERIODIC_CACHING,
      poolMaxSize: 10,
      batchIntervals: 100
    },
  initialBucketing: {},
  statusChangedCallback: function(status){
    console.log(status)
  },
  onBucketingSuccess: function(status, payload){
    console.log(status, payload)
  },
  onBucketingFail: function(error){
    console.log(error)
  },
  onBucketingUpdated: function(lastUpdate){
    console.log(lastUpdate)
  },
  onLog: (level, tag, message) => {
    console.log(`[${LogLevel[level]}] [${tag}] : ${message}`);
  }
});
import { Flagship, DecisionMode, LogLevel, CacheStrategy } from "https://deno.land/x/flagship_io_js_sdk/mod.ts";

Flagship.start("<ENV_ID>", "<API_KEY>", {
  decisionMode: DecisionMode.BUCKETING,
  fetchNow: false,
  timeout: 10,
  enableClientCache: true,
  logLevel: LogLevel.CRITICAL,
  logManager: sentryMiddleware,
  decisionApiUrl: 'https://example.com',
  pollingInterval: 100,
  activateDeduplicationTime: 0,
  hitDeduplicationTime: 0,
  trackingMangerConfig: {
      cacheStrategy: CacheStrategy.PERIODIC_CACHING,
      poolMaxSize: 10,
      batchIntervals: 100
    },
  initialBucketing: {},
  statusChangedCallback: function(status){
    console.log(status)
  },
  onBucketingSuccess: function(status, payload){
    console.log(status, payload)
  },
  onBucketingFail: function(error){
    console.log(error)
  },
  onBucketingUpdated: function(lastUpdate){
    console.log(lastUpdate)
  },
  onLog: (level, tag, message) => {
    console.log(`[${LogLevel[level]}] [${tag}] : ${message}`);
  }
});

Below the details of every attribute you can set inside the SDK config object :

AttributeTypeDefaultDescription
decisionModeDECISION-API|BUCKETING|BUCKETING_EDGEDECISION-APISpecify the SDK running mode. see Decision Mode
fetchNowbooleantrueIf it's set to true, it will call automatically fetchFlags when creating a new Visitor
timeoutnumber2Specify timeout in seconds for api request.
Note: timeout can't be lower than 0 second.
enableClientCachebooleanfalseIndicates whether enables or disables the client cache manager.
By enabling the client cache, it will allow you to keep cross sessions visitor experience.
Note: The client cache is useful only when you do not specify a visitor id when creating a visitor. From there, you only need to be focus on handling the visitor context and whether he is authenticated or not. That's it.
Note2: Not available on server side, this setting will be ignored
logLevelnumber9Set the maximum log level to display
seeLogLevel
logManagerobjectDefinedSpecify a custom implementation of LogManager in order to receive logs from the SDK.
Note: The object must fill Interface IFlagshipLogManager
decisionApiUrlstringhttps://decision.flagship.io/v2This setting can be useful if you need to simulate the API for tests such as end-to-end or if you want to move to an earlier version of the Flagship API.
pollingIntervalnumber1Specify delay in seconds between two bucketing polling when SDK is running on Bucketing mode.
Note: If 0 is given, it should poll only once at start time.
hitDeduplicationTimenumber2.5You can specify a delay in seconds for hit deduplication. After a hit is sent, any future attempts to send the same hit will be blocked until the specified delay has expired.
Note: If a value of 0 is given, no deduplication process will be used.
initialBucketingobjectundefinedOptional
You can define an object containing the data received when fetching the bucketing endpoint. Providing this object will make bucketing ready to use and the first polling will immediately check for updates.
visitorCacheImplementationobjectDefined on client side and undefined on server sideOptional
Define an object that implement the interface visitorCacheImplementation interface to manage hits cache. see cache-manager
hitCacheImplementationobjectDefined on client side and undefined on server sideOptional
You can define an object that implements the IHitCacheImplementation, to handle the visitor cache. see cache-manager
disableCachebooleanfalseif it's set to true, hit cache and visitor cache will be disabled otherwise will be enabled. see cache-manager
statusChangedCallbackfunction(number):voidundefinedOptional
Define a callable in order to get callback when the SDK status has changed.
see arguments.
onBucketingSuccessfunction(object):voidundefinedOptional
Define a callable in order to get callback when the first bucketing polling succeed.
see arguments
onBucketingFailfunction(error):voidundefinedOptional
Define a callable to get callback when the first bucketing polling failed.
see arguments
onBucketingUpdatedfunction(object):voidundefinedOptional
Define a callable to get callback each time bucketing data from Flagship has updated.
see arguments
onUserExposure deprecatedfunction(object):voidundefinedOptional

Define a callable to get callback each time a Flag have been visitor exposed (activation hit has been sent) by SDK
see arguments

Note: deprecated use onVisitorExposed instead of
onLogfunction(level: LogLevel, tag: string, message: string):voidundefinedOptional
Define a callable to get a callback whenever the SDK needs to report a log
see arguments
trackingMangerConfigobjectdefinedDefine options to configure hit batching
trackingMangerConfig
onVisitorExposedfunction(object):voidundefinedOptional
Define a callable to get callback each time a Flag has been exposed to a visitor (When a flag has been seen by your visitor) and succeeded.

see arguments
fetchThirdPartyDatabooleanfalseOptional
Bucketing mode only
If true, will fetch the visitor's segment from universal data connector each time fetchFlags is called and append those segments in the visitor context
nextFetchConfigobject{ revalidate: 20 }In Next.js 13, you can define the time in seconds for storing SDK route cache before revalidation. learn more

Decision Mode

DECISION-API Mode (by default)

When the SDK operates in API mode, it uses our Decision API to manage campaign assignments and validate targeting. In this mode, each time a new Decision is needed, the SDK sends an HTTPS request to the API. This mode is enabled by default for all our SDKs.

Bucketing Mode

In Bucketing mode, the SDK downloads all campaign configurations in a single bucketing file. This allows the SDK to compute variation assignments on the client-side. The bucketing file is cached and only re-downloaded when campaign configurations are updated in the Flagship interface. Learn more

BUCKETING_EDGE Mode

This mode is recommended in Edge environnements, the SDK must be initialized with the bucketing file and variation assignment is computed locally by the SDK.

There is no automatic batching process, so the Flagship.close() method must be called manually to batch and send all hits once collected. Learn more

DecisionMode is an enum defined decision type

import { DecisionMode } from "@flagship.io/js-sdk";

//const mode = DecisionMode.DECISION_API;
const mode = DecisionMode.BUCKETING;

Flagship.start("<ENV_ID>", "<API_KEY>", {
  decisionMode:mode
});
import { DecisionMode } from "https://deno.land/x/flagship_io_js_sdk/mod.ts";

//const mode = DecisionMode.DECISION_API;
const mode = DecisionMode.BUCKETING;

Flagship.start("<ENV_ID>", "<API_KEY>", {
  decisionMode:mode
});
KeyValueTypeDescription
DECISION_APIDECISION-APIstringFlagship SDK mode Decision API
BUCKETINGBUCKETINGstringFlagship SDK mode bucketing
BUCKETING_EDGEBUCKETING_EDGEstringFlagship SDK mode bucketing edge

LogLevel

LogLevel is an enum defined the level of log to receive

import { LogLevel } from "@flagship.io/js-sdk";

const level = LogLevel.ERROR;

Flagship.start("<ENV_ID>", "<API_KEY>", {
  logLevel:level
});
import { LogLevel } from "https://deno.land/x/flagship_io_js_sdk/mod.ts";

const level = LogLevel.ERROR;

Flagship.start("<ENV_ID>", "<API_KEY>", {
  logLevel:level
});
KeyValueTypeDescription
NONE0intLogging will be disabled.
EMERGENCY1intOnly emergencies will be logged
ALERT2intOnly alerts and above will be logged.
CRITICAL3intOnly critical and above will be logged.
ERROR4intOnly errors and above will be logged.
WARNING5intOnly warnings and above will be logged.
NOTICE6intOnly notices and above will be logged.
INFO7intOnly info logs and above will be logged.
DEBUG8intOnly debug logs and above will be logged.
ALL9intEverything will be logged.

IFlagshipLogManager

The aims of this Interface is to define methods that an object must have in order to receive Flagship SDK logs

interface IFlagshipLogManager {
  emergency(message: string, tag: string): void;
  alert(message: string, tag: string): void;
  critical(message: string, tag: string): void;
  error(message: string, tag: string): void;
  warning(message: string, tag: string): void;
  notice(message: string, tag: string): void;
  info(message: string, tag: string): void;
  debug(message: string, tag: string): void;
  log(level: LogLevel, message: string, tag: string): void;
}
ArgumentTypeDescription
messagestringGet a description of the log
tagstringGet the function that triggered the log
levelnumberGet the log level.

Note: only for log method see LogLevel

Usage :

import { LogLevel, Flagship } from "@flagship.io/js-sdk";

const customLog = {
  emergency(message, tag) {
    this.log(LogLevel.EMERGENCY, message, tag);
  },

  alert(message, tag) {
    this.log(LogLevel.ALERT, message, tag);
  },

  critical(message, tag) {
    this.log(LogLevel.CRITICAL, message, tag);
  },

  error(message, tag) {
    this.log(LogLevel.ERROR, message, tag);
  },

  warning(message, tag) {
    this.log(LogLevel.WARNING, message, tag);
  },

  notice(message, tag) {
    this.log(LogLevel.NOTICE, message, tag);
  },

  info(message, tag) {
    this.log(LogLevel.INFO, message, tag);
  },

  debug(message, tag) {
    this.log(LogLevel.DEBUG, message, tag);
  },

  log(level, message, tag) {
    console.log(`[${LogLevel[level]}] [${tag}] : ${message}`);
  },
};

Flagship.start("<ENV_ID>", "<API_KEY>", {
  logManager: customLog,
  logLevel: LogLevel.ALL
});
import { LogLevel, Flagship } from "https://deno.land/x/flagship_io_js_sdk/mod.ts";

const customLog = {
  emergency(message, tag) {
    this.log(LogLevel.EMERGENCY, message, tag);
  },

  alert(message, tag) {
    this.log(LogLevel.ALERT, message, tag);
  },

  critical(message, tag) {
    this.log(LogLevel.CRITICAL, message, tag);
  },

  error(message, tag) {
    this.log(LogLevel.ERROR, message, tag);
  },

  warning(message, tag) {
    this.log(LogLevel.WARNING, message, tag);
  },

  notice(message, tag) {
    this.log(LogLevel.NOTICE, message, tag);
  },

  info(message, tag) {
    this.log(LogLevel.INFO, message, tag);
  },

  debug(message, tag) {
    this.log(LogLevel.DEBUG, message, tag);
  },

  log(level, message, tag) {
    console.log(`[${LogLevel[level]}] [${tag}] : ${message}`);
  },
};

Flagship.start("your_env_id", "your_api_key", {
  logManager: customLog,
  logLevel: LogLevel.ALL,
  fetchNow: false,
  timeout: 2,
});

FlagshipStatus

FlagshipStatus is an enum defining the different status of Flagship SDK

import { FlagshipStatus } from "@flagship.io/js-sdk";

const status = FlagshipStatus.READY;
import { FlagshipStatus } from "https://deno.land/x/flagship_io_js_sdk/mod.ts";

const status = FlagshipStatus.READY;
KeyValueTypeDescription
NOT_INITIALIZED0intIt is the default initial status. This status remains until the sdk has been initialized successfully.
STARTING1intFlagship SDK is starting.
POLLING2intFlagship SDK has been started successfully but is still polling campaigns.
READY_PANIC_ON3intFlagship SDK is ready but is running in Panic mode: All features are disabled except the one which refresh this status.
READY4intFlagship SDK is ready to use.

statusChangedCallback

The statusChangedCallback function has one argument

ArgumentTypeDescription
statusnumberStatus of the SDK. seeFlagshipStatus

onBucketingSuccess

The onBucketingSuccess function has one argument with the following shape:

Key/PropertyTypeDescription
statusnumberString. Returns either 200 (fresh update) or 304 (no change).
payloadobjectThe latest bucketing data received.

onBucketingFail

The onBucketingFail function has one argument

ArgumentTypeDescription
errorobjectReturns the error occurred

onBucketingUpdated

The onBucketingUpdated function has one argument

ArgumentTypeDescription
lastUpdateDateGet the date of the latest update

onUserExposure deprecated

The onUserExposure function has one argument with the following shape:

ArgumentTypeDescription
paramUserExposureInfoGet data from exposed flag

UserExposureType shape

type UserExposureInfo = {
  flagData: {
    key: string
    value: unknown
    metadata: IFlagMetadata
  },
  visitorData: {
    visitorId: string
    anonymousId: string|null
    context: Record<string, string|number|boolean>
  }
 }
Key/PropertyTypeDescription
flagDataobjectkey: flag key
value: flag value
metadata: Campaign information metadata see
visitorDataobjectvisitorId: visitor id
anonomousId: anonymous id
context: visitor context

OnVisitorExposed

In some cases, you'll need to send information about the exposure (When a flag has been seen by your visitor), like sending visitor and flag data to third parties.

To centralize it, we provide a callback in the configuration option of the SDK.

The OnVisitorExposed function has one argument with the following shape:

ArgumentTypeDescription
paramOnVisitorExposedGet data from exposed flag

OnVisitorExposed shape

type OnVisitorExposed ={
    exposedVisitor: {
      id: string
      anonymousId?:string|null
      context: Record<string, string|number|boolean>
  },
    fromFlag: {
      key: string
      value: unknown
      defaultValue: unknown
      metadata: IFlagMetadata
  }
}
Key/PropertyTypeDescription
exposedVisitorobjectThis object represent the exposed visitor
fromFlagobjectThis object represent the exposed flag.
(The flag that has triggered the exposure)

exposedVisitor object shape

Key/PropertyTypeDescription
idstringvisitor id
anonomousIdstringanonymous id
contextRecord<string, string|number|boolean>visitor context

fromFlag object shape

Key/PropertyTypeDescription
keystringflag key
valueunknownflag value
defaultValueunknownflag default value
metadataIFlagMetadataCampaign information metadata see

Here is an example on how to use this callback:

Example with Mixpanel integration
Example with Segment integration

Learn more about getting flags


onLog

The onLog function has 3 arguments

ArgumentTypeDescription
levelnumberGet the log level. see LogLevel
tagstringGet the function that triggered the log
messagestringGet a description of the log
import { LogLevel, Flagship } from "@flagship.io/js-sdk";


Flagship.start("<ENV_ID>", "<API_KEY>", {
  logLevel: LogLevel.ALL,
  onLog: (level, tag, message) => {
    console.log(`[${LogLevel[level]}] [${tag}] : ${message}`);
  }
});

trackingMangerConfig

The SDK features a batching system for sending hits, which can be configured using three options: CacheStrategy, PoolMaxSize, and BatchIntervals. Using the TrackingManager’s batch processing reduces network traffic, prevents hit loss through caching, and resends any failed hits.

Hits are first added to an internal pool as they are emitted by visitors. The pool is then emptied by batching all hits and sending them when either the PoolMaxSize is reached or the BatchIntervals timer is triggered. If a batch fails, all hits within it are returned to the pool for future iteration and the cache is updated based on the selected cache strategy.

Note: At any time, when your app is about to close or crash, you should call Flagship.close() to batch and send all hits that are in the pool.

options:

KeyTypeDefault valueDescription
cacheStrategyCacheStrategy | numberCONTINUOUS_CACHING: 0 for browser
PERIODIC_CACHING: 1 for nodeJs and Deno
Define the strategy that will be used for hit caching
see cacheStrategy
poolMaxSizenumber10 for browser
100 for nodeJs and Deno
Define the minimum number of hits the pool must reach to automatically batch all hits in the pool and send it

Note:
- Must be greater than 5 otherwise default value will be used
- Having a large poolMaxSize can lead to performance issues
batchIntervalsnumber5s for browser
10s for nodeJs and Deno
Define a regular interval in seconds to trigger batch processing

Note:
- The process will batch all hits from the pool whether poolMaxSize is reached or not
- Must be between 1sec and 10800s (3hours). Otherwise default value will be applied

CacheStrategy

cacheStrategy is an enum defining the different caching strategies

KeyTypevalueDescription
CONTINUOUS_CACHINGnumber0When a hit is emitted, it will first be cached in database using IHitCacheImplementation and added into the pool, then after batching and sending, it will also be flushed from database using IHitCacheImplementation.

Note: the SDK has a default cache implementation for browser using localStorage

Note: recommended for client side applications

see example using localStorage
PERIODIC_CACHINGnumber1When a hit is emitted, it will be added into the pool, then after batching and sending, all database hits will be flushed, then the entire pool will be cached using IHitCacheImplementation for both actions.

Note: recommended for server-side applications

see example using redis
import { CacheStrategy, Flagship } from "@flagship.io/js-sdk";


Flagship.start(ENV_ID, API_KEY, {
    trackingMangerConfig: {
      cacheStrategy: CacheStrategy.PERIODIC_CACHING,
      poolMaxSize: 10,
      batchIntervals: 100
    }
 })

πŸ“˜

  • The CONTINUOUS_CACHING strategy (recommended for client side apps) should be used when your application is running in an environment where the probability of data loss is high.
    For example in a browser, a visitor can at any time reload the page and erase all data in memory.

Keep in mind that this strategy can do a lot of database I/O depending on how many hits your visitor can send.

  • The PERIODIC_CACHING strategy (recommended for server side apps) should be used when your application sends a lot of hits and the probability of data loss is low.

In this strategy, the number of I/Os in the database is low.



Other Flagship class methods

getStatus function

Return current status of Flagship SDK. seeFlagshipStatus

  • getStatus (): FlagshipStatus
  • static getStatus (): FlagshipStatus
import { Flagship } from "@flagship.io/js-sdk";

const fsInstance = Flagship.start("<ENV_ID>", "<API_KEY>");
const status = fsInstance.getStatus();

//or

const status = Flagship.getStatus();
import { Flagship } from "https://deno.land/x/flagship_io_js_sdk/mod.ts";

const fsInstance = Flagship.start("<ENV_ID>", "<API_KEY>");
const status = fsInstance.getStatus();

//or

const status = Flagship.getStatus();

getConfig function

Return the current config used by the SDK. see configuration attribute

  • getConfig (): IFlagshipConfig
  • static getConfig (): IFlagshipConfig

getVisitor function

Return the last visitor created and saved or return undefined if no visitor has been saved. see newVisitor.

  • getVisitor ():Visitor|undefined
  • static getVisitor ():Visitor|undefined

close function

Most of the time you don't need to manually close the SDK, but when your application is about to terminate, you should call the close method of the Flagship class to avoid data loss.

When called, it will batch and send all hits that are in the pool before the application is closed

  • close ():Promise<void>
  • static close ():Promise<void>


Create a visitor

The Visitor instance is an object that contains everything related to your visitor, its data but also the Decision of Flagship.

By creating a new visitor, you be able to set all the data relevant for Flagship to take a Decision and know your visitor, this includes :

The visitor context is a dataset (object) that defines your current visitor.
This dataset is sent to Flagship for targeting purposes (use-case assignment) but also to enrich your reporting with Context Filters.
You may have to sync with your team to know what data is useful for them to have into Flagship reporting.

By default, depending on IFlagshipConfig, this will automatically trigger a Decision of Flagship and will be available through the getFlag method

import { Flagship } from "@flagship.io/js-sdk";

const fsInstance = Flagship.start("<ENV_ID>", "<API_KEY>");

const fsVisitor = fsInstance.newVisitor({
  visitorId: "<VISITOR_ID>",
  context: {
   // <CONTEXT_KEY>: <CONTEXT_KEY>,
  }
});

// or 

const fsVisitor = Flagship.newVisitor({
  visitorId: "<VISITOR_ID>",
  context: {
   // <CONTEXT_KEY>: <CONTEXT_KEY>,
  }
});
import { Flagship } from "https://deno.land/x/flagship_io_js_sdk/mod.ts";

const fsInstance = Flagship.start("<ENV_ID>", "<API_KEY>");

const fsVisitor = fsInstance.newVisitor({
  visitorId: "<VISITOR_ID>",
  context: {
   // <CONTEXT_KEY>: <CONTEXT_KEY>,
  }
});

// or 

const fsVisitor = Flagship.newVisitor({
  visitorId: "<VISITOR_ID>",
  context: {
   // <CONTEXT_KEY>: <CONTEXT_KEY>,
  }
});

Let's take an example:
if you want to enable a specific feature to all your VIPs visitor,
you'll need to add this data as an attribute into the visitor context (key-value pair) in the visitor context: isVIP: true.
Based on your targeting criteria defined in your use-case (isVIP === true), Flagship will take the Decision and show your feature to visitors that at least contains isVIP in their context and for which isVIP is equal to true.

import { Flagship } from "@flagship.io/js-sdk";

const fsInstance = Flagship.start("<ENV_ID>", "<API_KEY>");

const fsVisitor = fsInstance.newVisitor({
  visitorId: "<VISITOR_ID>",
  isAuthenticated: true,
  hasConsented: true,
  context: {
    isVIP: true,
    country: "NL",
    loginProvider: "Google"
  }
});
import { Flagship } from "https://deno.land/x/flagship_io_js_sdk/mod.ts";

const fsInstance = Flagship.start("<ENV_ID>", "<API_KEY>");

const fsVisitor = fsInstance.newVisitor({
  visitorId: "<VISITOR_ID>",
  isAuthenticated: true,
  hasConsented: true,
  context: {
    isVIP: true,
    country: "NL",
    loginProvider: "Google"
  }
});

newVisitor function

Creates and returns a new Visitor or null if the SDK hasn't started successfully.

This method should always be called after the Flagship SDK has started.

  • static newVisitor (params: INewVisitor): Visitor | null

  • newVisitor (params: INewVisitor): Visitor | null

This method has only one argument with the following shape:

Key/PropertyTypeDefaultDescription
visitorIdstringundefinedOptional - Unique visitor identifier.
Note: It will be generated if not set

NOTE 2: In client side if you do not specify a value, the id will be either automatically generated or will be the visitor id from previous session (if enableClientCache equals true.
isAuthenticatedbooleanfalseSpecify if the visitor is authenticated or anonymous for Experience continuity.
hasConsentedbooleantrueSpecify if visitor has consented for protected data usage.
contextobject { [key: string]: string | number | boolean }{}Initial visitor context.
isNewInstancebooleantrue on server-side
false on client-side
If true The newly created visitor instance won't be saved and will simply be returned otherwise the newly created visitor instance will be returned and saved into the Flagship instance.
Note: will be default true on server-side and false on client-side
initialCampaignsobjectundefinedOptional - This is an object of the data received when fetching the Flagship decision API (decisionMode="API").
Providing this property avoid the SDK to have an empty cache during first initialization.
initialFlagsDataarrayundefinedOptional - This is a set of flag data provided to avoid the SDK to have an empty cache during the first initialization.

Flag data shape:

Key\PropertyTypeDescription
keystringName of flag
campaignIdstringID of the campaign
slugstringcampaign slug
campaignTypestringcampaign type
variationGroupIdstring
variationIdstringThe variation ID assigned to the visitor
isReferencebooleanSpecify if its the reference variation
valueanyValue of flag

🚧

  • When both initialCampaigns and initialFlags are provided, only initialFlags will be used.
  • Visitor context keys must have a type of string
  • Visitor context values must have a type of string, boolean, number
  • Visitor context keys and values are case sensitive

Updating the visitor context


The visitor context is a property dataset that defines the current visitor of your app. This dataset is sent and used as targeting criteria for campaign assignment.

The following method from the Visitor instance allows you to set new context values matching the given keys.

//... import code

Flagship.start("your_env_id", "your_api_key");

const visitor = Flagship.newVisitor({
  visitorId: "your_visitor_id",
  context: { age: 31, isVip: true },
});

visitor.updateContext({ lastPurchaseDate: 1615384464 });

updateContext function

Update the visitor context values, matching the given keys, used for targeting.

A new context value associated with this key will be created if there is no previous matching value.

  • public updateContext(context: Record<string, string | number | boolean>): void

It has one argument :

ArgumentTypeDescription
contextobjectA Set of keys, values.

context property

This property returns all the visitor's current context as an object

  • get context () : Record<string, string | number | boolean>

clearContext function

Clear the actual visitor context

  • clearContext(): void

🚧

  • Visitor context keys must have a type of string
  • Visitor context values must have a type of string, bool, numeric
  • Visitor context keys and values are case sensitive

update context with predefined keys of context

import { Flagship, DEVICE_LOCALE, OS_NAME } from "@flagship.io/js-sdk";

Flagship.start("your_env_id", "your_api_key");

const visitor = Flagship.newVisitor({
  visitorId: "your_visitor_id",
  context: { age: 31, isVip: true },
});

visitor.updateContext({
  [DEVICE_LOCALE]: "fr",
  [OS_NAME]: "Ubuntu",
});
import { Flagship, DEVICE_LOCALE, OS_NAME } from "https://deno.land/x/flagship_io_js_sdk/mod.ts";

Flagship.start("your_env_id", "your_api_key");

const visitor = Flagship.newVisitor({
  visitorId: "your_visitor_id",
  context: { age: 31, isVip: true },
});

visitor.updateContext({
  [DEVICE_LOCALE]: "fr",
  [OS_NAME]: "Ubuntu",
});

Learn more about predefined keys of context



Managing visitor campaigns


Fetching Flags

The fetchFlags() method of the Visitor instance, according to Decision Mode, will either automatically call the Flagship Decision API to run campaign assignments according to the current visitor context and retrieve applicable flags,
or check bucketing file, validate campaigns targeting the visitor, assign a variation and retrieve applicable flags

These flags are then stored in the SDK and updated asynchronously when fetchFlags() is called.


//... import code

Flagship.start("your_env_id", "your_api_key");

const visitor = Flagship.newVisitor({
  visitorId: "your_visitor_id",
  context: { key: "value" },
});

visitor.fetchFlags().then(() => {
  //ready to use all features from the SDK
});

fetchFlags function

In DecisionApi Mode this function calls the Flagship Decision API to run campaign assignments according to the current visitor context and retrieve applicable flags.

In bucketing Mode, it checks bucketing file, validates campaigns targeting the visitor, assigns a variation and retrieve applicable flags

  • fetchFlags(): Promise<void>

Event listeners

The Visitor instance includes event listeners to help you handle the SDK.

Event listenerDescription
readyOnce it's called, you are ready to use all features from the SDK.
Note: It'll be called each time fetchFlags has updated stored flags

❗️

Before using any function from Visitor, it is important to follow one of the 3 ways describe below to ensure everything is working properly and your visitor is up to date with campaigns assignment.


Getting flags

Once the campaign has been assigned and fetched, all the flags are stored in the SDK. You can retrieve them using the fetchFlags functions from the Visitor instance.

There are 3 ways to be ready to use your flags:

  • With event listerner
  • With await statement
  • With then function

//...import code

Flagship.start("your_env_id", "your_api_key");

const visitor = Flagship.newVisitor({
  visitorId: "your_visitor_id",
  context: { isVip: true },
});

visitor.on("ready",  (error) => {
  if (error) {
    //do some stuff
    return;
  }

  //Get flag displayVipFeature
  const flag = visitor.getFlag("displayVipFeature", false);

  //do some stuff
});

visitor.fetchFlags();
//...import code

Flagship.start("your_env_id", "your_api_key");

const visitor = Flagship.newVisitor({
  visitorId: "your_visitor_id",
  context: { isVip: true },
});

await visitor.fetchFlags();

// Get flag displayVipFeature
const flag = visitor.getFlag("displayVipFeature", false);
//...import code

Flagship.start("your_env_id", "your_api_key");

const visitor = Flagship.newVisitor({
  visitorId: "your_visitor_id",
  context: { isVip: true },
});

visitor.fetchFlags().then(()=>{
  // Get flag displayVipFeature
  const flag = visitor.getFlag("displayVipFeature", false);
});

getFlag function

Return a Flag object by its key. If no flag match the given key an empty flag will be returned. Call exists() to check if the flag has been found.

  • getFlag<T>(key:string, defaultValue: T):IFlag<T>

ArgumentTypeDescription
keyStringkey associated to the flag.
defaultValueTflag default value.

🚧

  • Default value must be one of the following type : string, number, boolean, object, array or null.
  • When the defaultValue is null, no type checking will be performed

Getting flags current values

getValue function

To retrieve flag current value, simply call getValue() method of the Flag object.

//...import code

Flagship.start("your_env_id", "your_api_key");

const visitor = Flagship.newVisitor({
  visitorId: "your_visitor_id",
  context: { isVip: true },
});

visitor.on("ready", (error) => {
  if (error) {
    //do some stuff
    return;
  }

  //Get flag displayVipFeature
  const flagValue = visitor.getFlag("displayVipFeature", false).getValue();

  //do some stuff
});

visitor.fetchFlags();
  • getValue(visitorExposed : boolean) : T function

Returns the value from the assigned campaign variation or the Flag default value if the Flag does not exist, or if types are different.

ParameterTypeDefault ValueDescription
visitorExposedBooleantrueTells Flagship the visitor have been exposed and have seen this flag. This will increment the visits for the current variation on your campaign reporting.
If needed it is possible to set this param to false and call visitorExposed() afterward when the visitor sees it.

Getting flags campaigns metadata

metadata property

You may need to send campaign IDs or variation IDs to a third party for reporting and/or analytics purposes. It is possible to retrieve campaigns metadata for a specific Flag.


//...import code

Flagship.start("your_env_id", "your_api_key");

const visitor = Flagship.newVisitor({
  visitorId: "your_visitor_id",
  context: { isVip: true },
});

visitor.on("ready", (error) => {
  if (error) {
    //do some stuff
    return;
  }

  //Get flag displayVipFeature
  const campaignMetada = visitor.getFlag("displayVipFeature", false).metadata;

  //do some stuff
});

visitor.fetchFlags();
  • metadata:IFlagMetadata

Return the campaign information metadata or an empty object if the Flag doesn't exist or if the default value type does not correspond to the Flag type in Flagship.

interface IFlagMetadata{
    campaignId:string
    variationGroupId:string
    variationId: string
    isReference: boolean
    campaignType: string
    slug?:string|null
}
Key\PropertyTypeDescription
campaignIdstringID of the campaign
variationGroupIdstring
variationIdstringThe variation ID assigned to the visitor
isReferencebooleanSpecify if its the reference variation
campaignTypestringcampaign type
slugstringcampaign slug

Report a Flag exposure

visitorExposed function

By default when the method getValue() is called, The SDK considers that the visitor have seen the effets of your Flag, unless you pass false to getValue(). In this case you will have to call visitorExposed().

There are two ways for exposing a visitor to a flag:

  1. Pass an visitorExposed=true parameter to the getValue() method.
  2. Use the following visitorExposed() method from the Flag instance.

//...import code

Flagship.start("your_env_id", "your_api_key");

const visitor = Flagship.newVisitor({
  visitorId: "your_visitor_id",
  context: { isVip: true },
});

visitor.on("ready", (error) => {
  if (error) {
    //do some stuff
    return;
  }

  //Get flag displayVipFeature
  const flag = visitor.getFlag("displayVipFeature", false);
  const value = flag.getValue(false);
  
  //Report a flag exposure
  flag.visitorExposed();

  //do some stuff
});

visitor.fetchFlags();

  • visitorExposed(): Promise<void>

Tells Flagship the visitor have been exposed and have seen this flag. This will increment the visits for the current variation on your campaign reporting. No visitor exposure will be sent if the Flag doesn't exist or if the default value type do not correspond to the Flag type in Flagship.



  • userExposed(): Promise<void> deprecated

Tells Flagship the visitor have been exposed and have seen this flag. This will increment the visits for the current variation on your campaign reporting. No visitor exposure will be sent if the Flag doesn't exist or if the default value type do not correspond to the Flag type in Flagship.

🚧

userExposed is deprecated, use visitorExposed instead


Check if a Flag exists

exists function

This method will return true if a Flag exists in Flagship

  • exists(): boolean
//...import code

Flagship.start("your_env_id", "your_api_key");

const visitor = Flagship.newVisitor({
  visitorId: "your_visitor_id",
  context: { isVip: true },
});

visitor.on("ready", (error) => {
  if (error) {
    //do some stuff
    return;
  }

  const isDisplayVipFeature = visitor.getFlag("displayVipFeature", false).exists();

  //do some stuff
});

visitor.fetchFlags();


Managing visitor consent

The Visitor class provides a method to let you manage visitor consent for data privacy usage. When False, campaign activation and hits will be disabled.
There are 2 ways to set visitor consent :

  1. Set hasConsented key to true when creating a new visitor
  2. Use setConsent method of visitor instance

//... import code

Flagship.start("your_env_id", "your_api_key");

const visitor = Flagship.newVisitor({
  visitorId: "your_visitor_id",
  hasConsented: true, // set hasConsented to true
  context: { isVip: true },
});

// or use setConsent method
visitor.setConsent(true);

setConsent function

Set if visitor has consented for protected data usage.

  • setConsent(hasConsented: boolean): void
ArgumentTypeDefaultDescription
hasConsentedbooleanrequiredSet visitor consent for private data usage. When false some features will be deactivated.

hasConsented property

Return True if the visitor has consented for private data usage, otherwise return False.

  • hasConsented: boolean

πŸ“˜

When a visitor sets consent to false, the data collection features (visitorExposed and sendHit) will be deactivated for them and all hits related to the visitor will be flushed from the pool and the cache.



Experience Continuity

Dealing with anonymous and logged-in visitors, Experience continuity allows you to maintain consistency between sessions and devices.

🚧

Make sure that the Experience continuity option is enabled on the Flagship platform before using those methods.

Authenticate

There are 2 ways to authenticate a visitor:

  1. Set key isAuthenticated to true when creating a new visitor
  2. Use authenticate method of Visitor instance

Authenticate anonymous visitor

  • authenticate(visitorId: string): void
ArgumentTypeDefaultDescription
visitorIdstringrequiredid of the new authenticated visitor.

🚧

Because we have changed the visitor data, we have to call the fetchFlags method after calling this one to update the decision from Flagship.

The targeting / Flags could be different for the visitor.


Unauthenticate

This function change authenticated Visitor to anonymous visitor

  • unauthenticate(): void

🚧

Because we have changed the visitor datas, we have to call the fetchFlags method after calling this one to update the decision from Flagship.

The targeting / Flags could be different for the visitor.

Code example

Let's assume basic scenario to understand how things work:

1. Your visitor arrives on your app for the first time.

We need to initialize the visitor but as we don't know anything about this visitor, we'll create a random visitor id or let the SDK do it for us. You can also specify some visitor context if necessary.

const visitor = Flagship.newVisitor({
  context: { key: "value" }
});

Here we don't set visitorId property so the SDK has auto-created an id for our visitor.

Regardless of how it has been set, the actual visitor id will be what we call the anonymous id.

2. Your visitor is signing in.

To tell the SDK about this status modification, you'll have to call the authenticate function which takes the required visitor id as argument.

// Example 
// You fetch the visitor_id from your DB
// let visitorId = db.getVisitorId();

visitor.authenticate(visitorId);

// Since your visitor has changed (is now logged-in)
// You have to check if the proper targeting and flags are set

visitor.fetchFlags()

The visitor is updated as authenticated, keeping the previous variations from campaigns that are still matched and thus gives you same flags as before being logged in.

πŸ“˜

Keep in mind that if the visitor also has its context changed, you might still have changes on flags as your visitor might target new campaigns.

3. Your visitor decides to sign out.

If you want to keep the same visitor experience, then you should do:

visitor.unauthenticate();

// Since your visitor has changed (is now logged-out)
// You have to check if the proper targeting and flags are set

visitor.fetchFlags();

Final implementation example

// Create a visitor 

const visitor = Flagship.newVisitor({
  context: { key: "value" }
});

// Call the authenticate function

visitor.authenticate(visitorId);

// Fetch the flags to update the visitor decision

visitor.fetchFlags();

// ... Do things ....

// If you want to unauthenticate the visitor 

visitor.unauthenticate();

// Fetch the flags to update the visitor decision

visitor.fetchFlags();

Other visitor instance member

getFlagsDataArray function

Return an array of all flags data fetched for the current visitor.

  • getFlagsDataArray():FlagDTO[]

getAllFlagsData function

The getAllFlagsData method returns a Promise<object> containing all the data for all the campaigns associated with the current visitor.

The object resolved by the promise has the same shape as the Decision API response (normal mode).

  • getAllFlagsData(activate : boolean) : Promise<{ visitorId: string; campaigns: CampaignDTO[];}>

The function takes the following arguments:

AttributeTypeDefaultDescription
activatebooleanfalseEnables modifications while getting them. NOTE: If modifications have already been retrieved, the activation will be sent in another request.

getFlagsDataForCampaign function

Useful to request the data for a specific campaign.

  • getModificationsForCampaign(campaignId: string, activate: boolean): Promise<{visitorId: string; campaigns: CampaignDTO[];}>;

The function takes the following arguments:

AttributeTypeDefaultDescription
campaignIdstringRequiredIdentifies the campaign whose modifications you want to retrieve. **See description
activatebooleanfalseEnables modifications while getting them. NOTE: If modifications have already been retrieved, the activation will be sent in another request.


Hit Tracking


This section helps you track your visitors in your application and learn how to build hits in order to feed your reports. For more information about our measurement protocol, read our Universal Collect documentation.

There are five different types of Hits available:

  • Page
  • Screen
  • Transaction
  • Item
  • Event

HitType

import { HitType } from "@flagship.io/js-sdk";

const page = HitType.PAGE;
import { HitType } from "https://deno.land/x/flagship_io_js_sdk/mod.ts";

const page = HitType.PAGE;
KeytypeValueDescription
PAGEstringPAGEVIEWVisitor has seen a URL.
SCREENstringSCREENVIEWVisitor has seen a screen.
TRANSACTIONstringTRANSACTIONVisitor has made a transaction.
ITEMstringITEMItem bought in a transaction.
EVENTstringEVENTVisitor has made a specific action.

They must all be built and sent with the following function from the Visitor instance:


import { Flagship, HitType } from "@flagship.io/js-sdk";

Flagship.start("your_env_id", "your_api_key");

const visitor = Flagship.newVisitor({
  visitorId: "your_visitor_id",
  hasConsented: true, // set hasConsented to true
  context: { isVip: true },
});

visitor.sendHit({
  type: HitType.PAGE,
  documentLocation: "https://localhost",
});

//or

visitor.sendHits([
  {
    type: HitType.PAGE,
    documentLocation: "https://localhost",
  },
  {
    type: HitType.SCREEN,
    documentLocation: "home",
  },
]);
import { Flagship, HitType } from "https://deno.land/x/flagship_io_js_sdk/mod.ts";

Flagship.start("your_env_id", "your_api_key");

const visitor = Flagship.newVisitor({
  visitorId: "your_visitor_id",
  hasConsented: true, // set hasConsented to true
  context: { isVip: true },
});

visitor.sendHit({
  type: HitType.PAGE,
  documentLocation: "https://localhost",
});

//or

visitor.sendHits([
  {
    type: HitType.PAGE,
    documentLocation: "https://localhost",
  },
  {
    type: HitType.SCREEN,
    documentLocation: "home",
  },
]);

sendHit function

Send Hit to Flagship servers for reporting.

  • sendHit (hit: IHit): Promise<void>
ParameterTypeDefaultDescription
hitobjectrequiredHit to send. see Hit

sendHits function

Send Hits to Flagship servers for reporting.

  • sendHits (hits: IHit[]): Promise<void>
ParameterTypeDefaultDescription
hitArray<object>requiredA set of Hit to send. see Hit

Hit common optional parameters


import { HitType } from "@flagship.io/js-sdk";

visitor.sendHit({
  type: HitType.PAGE,
  documentLocation: "https://localhost",
  userIp: "127.0.0.1",
  screenResolution: "800X600",
  locale: "fr",
  sessionNumber: "1234",
});
import { HitType } from "https://deno.land/x/flagship_io_js_sdk/mod.ts";

visitor.sendHit({
  type: HitType.PAGE,
  documentLocation: "https://localhost",
  userIp: "127.0.0.1",
  screenResolution: "800X600",
  locale: "fr",
  sessionNumber: "1234",
});

ParameterTypeDescription
userIpString(Optional) Visitor IP
screenResolutionstring(Optional) Screen resolution.
localeString(Optional) Visitor language
sessionNumberstring(Optional) Session number

Page


This hit should be sent each time a visitor arrives on a new page.

import { HitType } from "@flagship.io/js-sdk";

visitor.sendHit({
  type: HitType.PAGE, //or "PAGEVIEW"
  documentLocation: "https://www.my_domain_com/my_page",
});
import { HitType } from "https://deno.land/x/flagship_io_js_sdk/mod.ts";

visitor.sendHit({
  type: HitType.PAGE, //or "PAGEVIEW"
  documentLocation: "https://www.my_domain_com/my_page",
});

  • A hit of type Page has this following structure:
Key/PropertyTypeDefaultDescription
typestring (PAGEVIEW)requiredtype of hit. see HitType
documentLocationStringrequiredValid url.

Screen


This hit should be sent each time a visitor arrives on an interface on client side.

import { HitType } from "@flagship.io/js-sdk";

visitor.sendHit({
  type: HitType.SCREEN, //or "SCREENVIEW"
  documentLocation: "home_screen",
});
import { HitType } from "https://deno.land/x/flagship_io_js_sdk/mod.ts";

visitor.sendHit({
  type: HitType.SCREEN, //or "SCREENVIEW"
  documentLocation: "home_screen",
});

  • A hit of type Screen has this following structure:
Key/PropertyTypeDefaultDescription
typestring (SCREENVIEW)requiredType of hit. see HitType
documentLocationStringrequiredName of screen.

Transaction


This hit should be sent when a visitor completes a Transaction.

import { HitType } from "@flagship.io/js-sdk";

visitor.sendHit({
  type: HitType.TRANSACTION, //or "TRANSACTION"
  transactionId: "#12345",
  affiliation: "affiliation",
  taxes: 19.99,
  currency: "USD",
  couponCode: "code",
  itemCount: 1,
  shippingMethod: "road",
  shippingCosts: 5,
  paymentMethod: "credit_card",
  totalRevenue: "199.99",
});
import { HitType } from "https://deno.land/x/flagship_io_js_sdk/mod.ts";

visitor.sendHit({
  type: HitType.TRANSACTION, //or "TRANSACTION"
  transactionId: "#12345",
  affiliation: "affiliation",
  taxes: 19.99,
  currency: "USD",
  couponCode: "code",
  itemCount: 1,
  shippingMethod: "road",
  shippingCosts: 5,
  paymentMethod: "credit_card",
  totalRevenue: "199.99",
});

A hit of type TRANSACTION has this following structure:

Key/PropertyTypeDefaultDescription
typestring (TRANSACTION)requiredType of hit. see HitType
transactionIdStringrequiredUnique identifier for your transaction.
affiliationStringrequiredThe name of the KPI that you will have inside your reporting. Learn more
totalRevenuefloatoptionalSpecifies the total revenue associated with the transaction. This value should include any shipping and/or tax amounts.
shippingCostsfloatoptionalThe total shipping cost of your transaction.
shippingMethodStringoptionalThe shipping method for your transaction.
taxesfloatoptionalSpecifies the total amount of taxes in your transaction.
currencyStringoptionalSpecifies the currency of your transaction. NOTE: This value should be a valid ISO 4217 currency code.
paymentMethodStringoptionalSpecifies the payment method used for your transaction.
itemCountintoptionalSpecifies the number of items in your transaction.
couponCodeStringoptionalSpecifies the coupon code used by the customer in your transaction.

Item


This hit is used to link an item with a transaction. It must be sent after the corresponding transaction hit.

import { HitType } from "@flagship.io/js-sdk";

visitor.sendHit({
  type: HitType.ITEM, //or "ITEM"
  transactionId: "#12345",
  productName: "product",
  productSku: "sku123",
  itemPrice: 199.99,
  itemQuantity: 1,
  itemCategory: "test",
});
import { HitType } from "https://deno.land/x/flagship_io_js_sdk/mod.ts";

visitor.sendHit({
  type: HitType.ITEM, //or "ITEM"
  transactionId: "#12345",
  productName: "product",
  productSku: "sku123",
  itemPrice: 199.99,
  itemQuantity: 1,
  itemCategory: "test",
});

A hit of type ITEM has this following structure:

Key/PropertyTypeDefaultDescription
typestring (ITEM)requiredType of hit. see HitType
transactionIdStringrequiredUnique identifier for your transaction.
productNameStringrequiredName of your item.
productSkuStringrequiredSpecifies the SKU or item code.
itemCategoryStringoptionalSpecifies the category that the item belongs to.
itemPricefloatoptionalSpecifies the price for a single item/unit.
itemQuantityintoptionalSpecifies the number of items purchased.

πŸ“˜

The Item hit isn't available yet in the Flagship reporting view.


Event

This hit can be used for any event (e.g. Add To Cart click, newsletter subscription).


import { HitType, EventCategory } from "@flagship.io/js-sdk";

visitor.sendHit({
  type: HitType.EVENT, //or "EVENT"
  category: EventCategory.USER_ENGAGEMENT, // or EventCategory.ACTION_TRACKING
  action: "click",
  label: "label",
  value: 100,
});
import { HitType, EventCategory } from "https://deno.land/x/flagship_io_js_sdk/mod.ts";

visitor.sendHit({
  type: HitType.EVENT, //or "EVENT"
  category: EventCategory.USER_ENGAGEMENT, // or EventCategory.ACTION_TRACKING
  label: "label",
  value: 100,
});

A hit of type EVENT has this following structure:

Key/PropertyTypeDefaultDescription
typestring (EVENT)requiredType of hit. see HitType
categorystringrequiredSpecifies the category of your event. NOTE: This value must be either User Engagement or Action Tracking.
actionstringrequiredEvent name that will also serve as the KPI that you will have inside your reporting. Learn more
labelstringoptionalAdditional description of your event.
valueintegeroptional(optional) Can be used to evaluate visitor interactions with individual site objects or content items.
NOTE: this value must be non-negative / non-float


Managing visitor cache

The aims of the cache management is the response to the following problematic:

  • Re-allocation in bucketing mode :

In bucketing mode, the SDK will always keep visitor in variation where he was allocated first, in case of the customer or the dynamic allocation has changed the traffic allocation. Indeed in bucketing mode the assignation is made on local device so changing campaign allocation in the platform would make the visitors see different campaigns.

  • Handle offline mode on client side :

With the cache enabled, the SDK will try to retrieve the latest visitor data (campaign assignations) from the cache, also will save all the failed hits and visitorExposed in order to resend them later.


By default the Flagship JS SDK provide a default cache manager implementation on client side. It is possible to use your own cache manager by implementing the intefaces IVisitorCacheImplementation and IHitCacheImplementation through visitorCacheImplementation and hitCacheImplementation properties of configuration.

Visitor Cache

The visitor cache is used to store the visitor data in a database through the IVisitorCacheImplementation interface which defines the methods that an object must implement in order to handle it.

interface IVisitorCacheImplementation {
    cacheVisitor(visitorId: string, data: VisitorCacheDTO):Promise<void>
    lookupVisitor(visitorId: string): Promise<VisitorCacheDTO>
    flushVisitor(visitorId: string): Promise<void>
}

cacheVisitor function

This method is called when the SDK needs to cache visitor information in your database.

  • public cacheVisitor(visitorId: string, data: object):Promise<void>

It has 2 arguments :

ArgumentTypeDescription
visitorIdstringvisitor ID
Dataobjectvisitor data. The object follows the shape of type VisitorCacheDTO.

lookupVisitor function

This method is called when the SDK needs to get the visitor information corresponding to visitor ID from your database.

It has to return an object of type VisitorCacheDTO which follows this shape see.

  • public lookupVisitor(visitorId: string): Promise<object>

It has one argument :

ArgumentTypeDescription
visitorIdstringvisitor ID

flushVisitor function

This method is called when the SDK needs to erase the visitor information corresponding to visitor ID in your database.

It will be called every time setConsent get false.

  • public flushVisitor(visitorId: string): Promise<void>

It has one argument :

ArgumentTypeDescription
visitorIdstringvisitor ID

πŸ“˜

  • flushVisitor method will be called every time setConsent get false.

VisitorCacheDTO
type VisitorCacheDTO = {
  version: number;
  data: {
    visitorId: string;
    anonymousId: string | null;
    consent?: boolean;
    context?: Record<string, boolean|number|string>;
    assignmentsHistory?: Record<string, string>;
    campaigns?: Array<{
      campaignId: string;
      variationGroupId: string;
      variationId: string;
      isReference?: boolean;
      type: string;
      activated?: boolean;
      flags?: Record<string, unknown>;
    }>;
  };
};

Hit Cache

The hit cache is used to store hits in your database depending on strategy used through the IHitCacheImplementation interface which defines the methods that an object must implement to handle it.

interface IHitCacheImplementation {
    cacheHit(hits: Record<string, HitCacheDTO>):Promise<void>
    lookupHits():Promise<Record<string, HitCacheDTO>>
    flushHits(hitKeys: string[]): Promise<void>
    flushAllHits(): Promise<void>
}

cacheHit function

This method will be called to cache hits depending on cache strategy used.

  • public cacheHit(hits: Record<string, HitCacheDTO>):Promise<void>

It has 1 argument :

ArgumentTypeDescription
hitsobjectIt's a key/value object where the :
- key is a unique ID for each hit
- value is an object that follows the shape of type HitCacheDTO.

lookupHits function

This method will be called to load all hits from your database and trying to send them again in the background.

It has to return an object where the key is a unique ID for each hit and the value is an object of type HitCacheDTO which follows this shape see.

  • public lookupHits():Promise<Record<string, HitCacheDTO>>

flushHits function

This method will be called to erase all hits matching the unique Hits ID from your database.

NOTE: It will be called every time setConsent get false to erase all hits from database for visitor who set consent to false.

  • public flushHits(hitKeys: string[]): Promise<void>

It has one argument :

ArgumentTypeDescription
hitKeysArrayUnique ID of hits

flushAllHits function

This method will be called to erase all hits in your database without exception.

  • public flushAllHits(): Promise<void>

HitCacheDTO
type HitCacheLookupDTO = {
  version: number;
  data: {
    visitorId: string;
    anonymousId: string | null;
    type: HitType | "ACTIVATE";
    time: number;
    content?: Record<string, unknown>;
  };
};

πŸ“˜

  • flushHits method will be called every time setConsent get false.
  • Hits older than 4H will be ignored during the resending process.

IHitCacheImplementation implementation

localStorage

Implementation of IHitCacheImplementation interface using localstorage

import { Flagship, CacheStrategy } from "@flagship.io/js-sdk";

const FS_HIT_PREFIX = 'FS_DEFAULT_HIT_CACHE'


const hitCacheImplementation = {
  cacheHit (hits) {
    const localDatabaseJson = localStorage.getItem(FS_HIT_PREFIX) || '{}'
    const localDatabase = JSON.parse(localDatabaseJson)

    const newLocalDatabase = {
      ...localDatabase,
      ...hits
    }

    localStorage.setItem(FS_HIT_PREFIX, JSON.stringify(newLocalDatabase))
    return Promise.resolve()
  },
  lookupHits () {
    const localDatabaseJson = localStorage.getItem(FS_HIT_PREFIX) || '{}'
    const localDatabase = JSON.parse(localDatabaseJson)
    return Promise.resolve(localDatabase)
  },
  flushHits (hitKeys) {
    const localDatabaseJson = localStorage.getItem(FS_HIT_PREFIX) || '{}'
    const localDatabase = JSON.parse(localDatabaseJson)

    hitKeys.forEach(key => {
      delete localDatabase[key]
    })

    localStorage.setItem(FS_HIT_PREFIX, JSON.stringify(localDatabase))
    return Promise.resolve()
  },
  flushAllHits () {
    localStorage.removeItem(FS_HIT_PREFIX)
    return Promise.resolve()
  }
}

Flagship.start(ENV_ID, API_KEY, {
  hitCacheImplementation: hitCacheImplementation,
  trackingMangerConfig: {
    batchIntervals: 5,
    poolMaxSize: 10,
    cacheStrategy: CacheStrategy.CONTINUOUS_CACHING
  }
})

Redis

Implementation of IHitCacheImplementation interface using redis

import { Flagship, CacheStrategy } from "@flagship.io/js-sdk";
import Redis from 'ioredis'

function hitCacheImplementation (host, port, dbIndex) {
  const redis = new Redis({
    host,
    port
  })

  redis.select(dbIndex)

  return {

    async cacheHit (hits) {
      const multi = redis.multi()
      Object.entries(hits).forEach(([key, value]) => {
        multi.set(key, JSON.stringify(value))
      })
      await multi.exec()
    },
    async lookupHits () {
      const hits:Record<string, HitCacheDTO> = {}
      const keys = await redis.keys('*')
      if (!keys.length) {
        return hits
      }
      const redisData = await redis.mget(keys)

      redisData.forEach((value, index) => {
        if (!value) {
          return
        }
        hits[keys[index]] = JSON.parse(value)
      })
      return hits
    },
    async flushHits (hitKeys) {
      await redis.del(hitKeys)
    },

    async flushAllHits () {
      const keys = await redis.keys('*')
      if (!keys.length) {
        return
      }
      await redis.del(keys)
    }
  }
}

Flagship.start(ENV_ID, API_KEY, {
  hitCacheImplementation:hitCacheImplementation('127.0.0.1', '6379', 2),
  trackingMangerConfig: {
    batchIntervals: 10,
    poolMaxSize: 100,
    cacheStrategy: CacheStrategy.PERIODIC_CACHING
  }
})


API reference

Flagship class

Visitor class

Flag class


Appendix

Predefined visitor context keys :

The Flagship SDK contains predefined visitor context keys.

The keys marked as Yes in the Auto-set by SDK column will be automatically set, while the ones marked as No need to be set by customer.

You can overwrite these keys at any time. The keys-value pairs will be sent to the server in the visitor context and can be edited in the Persona section of the Flagship platform.

SDK constant NameDescriptionContext variable nameTypeAuto-set by SDKExample
DEVICE_LOCALELanguage of the devicesdk_deviceLanguageStringNofra
DEVICE_TYPEType of the devicesdk_deviceTypeDeviceTypeNoMobile
DEVICE_MODELModel of the devicesdk_deviceModelStringNosamsung E1200
LOCATION_CITYCity geolocationsdk_cityStringNotoulouse
LOCATION_REGIONRegion geolocationsdk_regionStringNooccitanie
LOCATION_COUNTRYCountry geolocationsdk_countryStringNoFrance
LOCATION_LATCurrent Latitudesdk_latDoubleNo43.623647
LOCATION_LONGCurrent Longitudesdk_longDoubleNo1.445397
IPIP of the devicesdk_ipStringNo127.0.0.1
OS_NAMEName of the OSsdk_osNameStringYESubuntu / centos
OS_VERSION_NAMEVersion name of the OSsdk_osVersionNameStringNo9.0.0
OS_VERSION_CODEVersion code of the OSsdk_osVersionCodeNumberNo24
CARRIER_NAMEName of the carrier or mobile virtual network operatorsdk_carrierNameStringNofree
INTERNET_CONNECTIONWhat is the internet connectionsdk_internetConnectionStringNo5g
APP_VERSION_NAMEVersion name of the appsdk_versionNameStringNo1.1.2-beta
APP_VERSION_CODEVersion code of the appsdk_versionCodeNumberNo40
INTERFACE_NAMEName of the interfacesdk_interfaceNameStringNoProductPage
FLAGSHIP_CLIENTFlagship SDK client (Reserved)fs_clientStringYesTS
FLAGSHIP_VERSIONVersion of the Flagship SDK (Reserved)fs_versionStringYes2.0.0
FLAGSHIP_VISITORCurrent visitor id (Reserved)fs_usersStringYesvisitor_id

πŸ“˜

To overwrite the keys, use the updateContext method