Javascript SDK Getting Started

• If the JS SDK is installed using NPM, call initializeDevCycle with your client key, a user object, and an optional options object.
• Otherwise, If you’re using the CDN to install the JS SDK, call DevCycle.initializeDevCycle with your client key, a user object, and an optional options object.

The user object needs either a user_id, or isAnonymous set to true for an anonymous user. The options object is optional, but can passed a logWriter for a custom logging solution and a logLevel, which must be one of info, debug, warn or error. The default options are to set the logWriter to be the console and the logLevel to error.

const user = { user_id: 'my_user' }
const dvcOptions = { logLevel: 'debug' }
// replace initializeDevCycle with DevCycle.initializeDevCycle if using the CDN
const devcycleClient = initializeDevCycle(
  '<DEVCYCLE_CLIENT_SDK_KEY>',
  user,
  dvcOptions,
)

Deferred Initialization

In many cases, user data is not available at the time of initialization. If the intialization call is made without a user object, then by default the SDK will be instantiated with an "anonymous" user and a configuration will be downloaded from DevCycle. The SDK makes a call to get the configuration for anonymous user and initializes.

If you would like to defer initialization of the SDK until your user data is available, you can pass the deferInitialization option to the intializeDevCycle method. This will cause the SDK to not fetch a configuration until the devcycleClient.identifyUser method is called with the user data. Until that config is retrieved, all calls to retrieve variable values will return their default values.

const dvcOptions = { logLevel: 'debug', deferInitialization: true }
// replace initializeDevCycle with DevCycle.initializeDevCycle if using the CDN
const devcycleClient = initializeDevCycle(
  '<DEVCYCLE_CLIENT_SDK_KEY>',
  dvcOptions,
)

DevCycleUser Object

DevCycleUser Typescript Schema

Property	Type	Description
isAnonymous	Boolean	Boolean to indicate if the user is anonymous
user_id	String	Unique user ID
email	String	User's email
name	String	User's name
language	String	User's language
country	String	User's country
appVersion	String	App version
appBuild	Number	App build
customData	DVCJSON	Key/value map of properties to be used for targeting
privateCustomData	DVCJSON	Key/value map of properties to be used for targeting. Private properties will not be included in event logging.

Initialization Options

The SDK exposes various initialization options which can be set on the initialization() method:

DevCycleOptions Typescript Schema

DevCycle Option	Type	Description
enableEdgeDB	Boolean	Enables the usage of EdgeDB for DevCycle that syncs User Data to DevCycle.
logger	DVCLogger	Logger override to replace default logger
logLevel	DVCDefaultLogLevel	Set log level of the default logger. Options are: debug, info, warn, error. Defaults to info.
eventFlushIntervalMS	Number	Controls the interval between flushing events to the DevCycle servers in milliseconds, defaults to 10 seconds.
flushEventQueueSize	Number	Controls the maximum size the event queue can grow to until a flush is forced. Defaults to 100.
maxEventQueueSize	Number	Controls the maximum size the event queue can grow to until events are dropped. Defaults to 1000.
apiProxyURL	String	Allows the SDK to communicate with a proxy of DevCycle bucketing API / client SDK API.
configCacheTTL	Number	The maximum allowed age of a cached config in milliseconds, defaults to 7 days
disableConfigCache	Boolean	Disable the use of cached configs
disableRealtimeUpdates	Boolean	Disable Realtime Updates
deferInitialization	Boolean	Defer initialization (fetching configuration from DevCycle) until user is identified with identifyUser call
disableAutomaticEventLogging	Boolean	Disables logging of sdk generated events (e.g. variableEvaluated, variableDefaulted) to DevCycle.
disableCustomEventLogging	Boolean	Disables logging of custom events, from track() method, and user data to DevCycle.