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App Configuration JavaScript client SDK

App Configuration JavaScript client SDK

To enhance the security of your applications using the ibm-appconfiguration-js-client-sdk, it is strongly recommended to use an encrypted APIKey instead of the plain APIKey in the init method. This change is vital to prevent exposure of sensitive credentials when users inspect your web application. If you are already using a plain APIKey, please update your application to generate and use the encrypted APIKey as per the steps mentioned here.

Overview

IBM Cloud App Configuration JavaScript Client SDK is used to perform feature flag and property evaluation in web applications and track custom metrics for Experimentation based on the configuration on IBM Cloud App Configuration service.

IBM Cloud App Configuration is a centralized feature management and configuration service on IBM Cloud for use with web and mobile applications, microservices, and distributed environments.

Instrument your web applications with App Configuration JavaScript Client SDK, and use the App Configuration dashboard, CLI or API to define feature flags or properties, organized into collections and targeted to segments. Toggle feature flag states in the cloud to activate or deactivate features in your application or environment, when required. Run experiments and measure the effect of feature flags on end users by tracking custom metrics. You can also manage the properties for distributed applications centrally.

Browser Compatibility: The SDK is supported on all major browsers. The Browser should have fetch() API support.

Integrating client SDK for JavaScript

Installation

Install the SDK. Use the following code to install as a module from package manager.

npm install ibm-appconfiguration-js-client-sdk

You can import the SDK into the script tag either by referencing it from a hosted site on your backend or from a CDN as follows:

Example:

<script type="text/javascript" src="https://unpkg.com/ibm-appconfiguration-js-client-sdk/dist/appconfiguration.js"></script>

Initialize SDK

Initialize the sdk to connect with your App Configuration service instance.

const region = AppConfiguration.REGION_US_SOUTH;
const guid = '<guid>';
const apikey = '<encrypted_apikey>';

const collectionId = 'airlines-webapp';
const environmentId = 'dev';

const appConfigClient = AppConfiguration.getInstance();

async function initialiseAppConfig() {
    appConfigClient.init(region, guid, apikey);
    await appConfigClient.setContext(collectionId, environmentId);
}

try {
    await initialiseAppConfig();
    console.log("app configuration sdk init successful");
} catch (e) {
    console.error("failed to initialise app configuration sdk", e);
}

In the above snippet, the async function initialiseAppConfig() will return an Promise<void> that resolves when the configurations are successfully fetched. Else, throws error if unsuccessful.

It is expected that initialisation to be done only once.

After the SDK is initialised successfully the feature flag & properties can be retrieved using the appConfigClient as shown in the below code snippet.

Expand to view the example snippet 
// other-file.js
const appConfigClient = AppConfiguration.getInstance();

const feature = appConfigClient.getFeature('online-check-in');
const result = feature.getCurrentValue(entityId, entityAttributes);
console.log(result);

const property = appConfigClient.getProperty('check-in-charges');
const result = property.getCurrentValue(entityId, entityAttributes);
console.log(result);

where,

  • region : Region name where the App Configuration service instance is created.
    • us-south for Dallas
    • eu-gb for London
    • au-syd for Sydney
    • us-east for Washington DC
    • eu-de for Frankfurt
  • guid : Instance ID of the App Configuration service. Obtain it from the service credentials section of the App Configuration dashboard.
  • apikey : The encrypted APIKey generated as described here.
  • collectionId: ID of the collection created in App Configuration service instance under the Collections section.
  • environmentId: ID of the environment created in App Configuration service instance under the Environments section.

Always use the encrypted APIKey to avoid exposing sensitive information.
Ensure that you create the service credentials with the Client SDK role, as it has the minimal access permissions that are suitable to use in browser-based applications.

Examples for using feature and property-related APIs

See the following examples for using the feature-related APIs.

Get single feature

const feature = appConfigClient.getFeature('featureId'); // throws error incase the featureId is invalid or doesn't exist
console.log(`Feature Name ${feature.getFeatureName()} `);
console.log(`Feature Id ${feature.getFeatureId()} `);
console.log(`Feature Type ${feature.getFeatureDataType()} `);

Get all features

const features = appConfigClient.getFeatures();
const feature = features['featureId'];

if (feature !== undefined) {
  console.log(`Feature Name ${feature.getFeatureName()} `);
  console.log(`Feature Id ${feature.getFeatureId()} `);
  console.log(`Feature Type ${feature.getFeatureDataType()} `);
  console.log(`Is feature enabled? ${feature.isEnabled()} `);
}

Evaluate a feature

Use the feature.getCurrentValue(entityId, entityAttributes) method to evaluate the value of the feature flag. This method returns one of the Enabled/Disabled/Overridden value based on the evaluation. The data type of returned value matches that of feature flag.

const entityId = 'john_doe';
const entityAttributes = {
  city: 'Bangalore',
  country: 'India',
};

const feature = appConfigClient.getFeature('featureId');
const featureValue = feature.getCurrentValue(entityId, entityAttributes);
  • entityId: Id of the Entity. This will be a string identifier related to the Entity against which the feature is evaluated. For example, an entity might be an instance of an app that runs on a mobile device, or a user accessing the web application. For any entity to interact with App Configuration, it must provide a unique entity ID.
  • entityAttributes: A JSON object consisting of the attribute name and their values that defines the specified entity. This is an optional parameter if the feature flag is not configured with any targeting definition. If the targeting is configured, then entityAttributes should be provided for the rule evaluation. An attribute is a parameter that is used to define a segment. The SDK uses the attribute values to determine if the specified entity satisfies the targeting rules, and returns the appropriate feature flag value.

Send custom metrics

Record custom metrics to use in experimentation using the track function.

appConfigClient.track(eventKey, entityId)

where

  • eventKey: The event key for the metric associated with the running experiment. The event key in your metric and the event key in your code must match exactly.

Get single property

const property = appConfigClient.getProperty('propertyId'); // throws error incase the propertyId is invalid or doesn't exist
console.log(`Property Name ${property.getPropertyName()} `);
console.log(`Property Id ${property.getPropertyId()} `);
console.log(`Property Type ${property.getPropertyDataType()} `);

Get all properties

const properties = appConfigClient.getProperties();
const property = properties['propertyId'];

if (property !== undefined) {
  console.log(`Property Name ${property.getPropertyName()} `);
  console.log(`Property Id ${property.getPropertyId()} `);
  console.log(`Property Type ${property.getPropertyDataType()} `);
}

Evaluate a property

Use the property.getCurrentValue(entityId, entityAttributes) method to evaluate the value of the property. This method returns the default property value or its overridden value based on the evaluation. The data type of returned value matches that of property.

const entityId = 'john_doe';
const entityAttributes = {
  city: 'Bangalore',
  country: 'India',
};

const property = appConfigClient.getProperty('propertyId');
const propertyValue = property.getCurrentValue(entityId, entityAttributes);
  • entityId: Id of the Entity. This will be a string identifier related to the Entity against which the property is evaluated. For example, an entity might be an instance of an app that runs on a mobile device, or a user accessing the web application. For any entity to interact with App Configuration, it must provide a unique entity ID.
  • entityAttributes: A JSON object consisting of the attribute name and their values that defines the specified entity. This is an optional parameter if the property is not configured with any targeting definition. If the targeting is configured, then entityAttributes should be provided for the rule evaluation. An attribute is a parameter that is used to define a segment. The SDK uses the attribute values to determine if the specified entity satisfies the targeting rules, and returns the appropriate property value.

Logging

Set the logging level to one of 'debug' | 'info' | 'warning' | 'error'. The default logging level is info.

appConfigClient.setLogLevel('debug');

Supported Data types

App Configuration service allows to configure the feature flag and properties in the following data types : Boolean, Numeric, String. The String data type can be of the format of a text string , JSON or YAML. The SDK processes each format accordingly as shown in the below table.

View Table
Feature or Property value DataType DataFormat Type of data returned
by getCurrentValue()		 Example output
true BOOLEAN not applicable boolean true
25 NUMERIC not applicable number 25
"a string text" STRING TEXT string a string text 
{
  "firefox": {
    "name": "Firefox",
    "pref_url": "about:config"
  }
}
 STRING JSON JSON object {"firefox":{"name":"Firefox","pref_url":"about:config"}} 
men:
  - John Smith
  - Bill Jones
women:
  - Mary Smith
  - Susan Williams
 STRING YAML string

`"men:

  • John Smith
  • Bill Jones
    women:
  • Mary Smith
  • Susan Williams"`
Feature flag usage Example 
const feature = appConfigClient.getFeature('json-feature');
feature.getFeatureDataType(); // STRING
feature.getFeatureDataFormat(); // JSON

// Example (traversing the returned JSON)
let result = feature.getCurrentValue(entityId, entityAttributes);
console.log(result.key) // prints the value of the key

const feature = appConfigClient.getFeature('yaml-feature');
feature.getFeatureDataType(); // STRING
feature.getFeatureDataFormat(); // YAML
feature.getCurrentValue(entityId, entityAttributes); // returns the stringified yaml (check above table)
Property usage example 
const property = appConfigClient.getProperty('json-property');
property.getPropertyDataType(); // STRING
property.getPropertyDataFormat(); // JSON

// Example (traversing the returned JSON)
let result = property.getCurrentValue(entityId, entityAttributes);
console.log(result.key) // prints the value of the key

const property = appConfigClient.getProperty('yaml-property');
property.getPropertyDataType(); // STRING
property.getPropertyDataFormat(); // YAML
property.getCurrentValue(entityId, entityAttributes); // returns the stringified yaml (check above table)

Set listener for feature and property data changes

The SDK provides an event-based mechanism to notify you in real-time when feature flag's or property's configuration changes. You can listen to configurationUpdate event using the same appConfigClient.

appConfigClient.emitter.on('configurationUpdate', () => {
  // **add your code**
  // To find the effect of any configuration changes, you can call the feature or property related methods

  // feature = appConfigClient.getFeature('online-check-in');
  // newValue = feature.getCurrentValue(entityId, entityAttributes);
});

Examples

Try this sample application in the examples folder to learn more about feature and property evaluation.

License

This project is released under the Apache 2.0 license. The license's full text can be found in LICENSE