JavaScript Frontend Web Client for Dynamic Configuration.

Usage

Either initialise directly from the feature-flag-service:

import { ConfigClient } from '@atlaskit/web-config-client';

const config = await ConfigClient.fetch({
	// Base URL of the feature-flag-service
	ffsBaseUrl: 'https://api.dev.atlassian.com/flags',
	// Your feature-flag-service API key, you can get it from:
	// https://developer.atlassian.com/platform/frontend-feature-flags/resources/api-keys/
	ffsApiKey: 'api-xxxx',
	// User context to evaluate the configuration against
	context: {
		namespace: 'switcheroo_web',
		identifiers: {
			atlassianAccountId: 'asdf',
		},
		metadata: {
			hasSomeTrait: true,
		},
	},
});

Or, initialise from values, where the values could come from your own service:

import { ConfigCollection } from '@atlassian/js-config-client-beta';

const config = ConfigCollection.fromValues(myValuesPayloadFromMyBackend);

And then start consuming your configuration:

const result = config.getNumber('rate-limit');
if (result.error) {
	// TODO: handle error
} else {
	console.log(result.value); // 42
}

Modes of Operation

There are currently 2 modes of operation:

• STANDARD
• This is the normal mode, everything will work as expected
• MINIMAL
• Smaller JSON formats are used in order to save on bytes transferred
• Boolean configurations which are false are not sent
  • This means that config.getBoolean("my-config") will return { error: NotFound } for any boolean configuration that's false
  • This is in order to save as much bytes as possible when sending over the configuration payloads

An example demonstrating the differences:

// --- Standard mode -------------------------------------------------------------------------------
const config = ConfigCollection.fromValues(STANDARD_PAYLOAD);
const result = config.getBoolean('my_config');

if (result.error === ConfigError.NotFound) {
	console.log("The configuration 'my_config' does not exist");
}

// --- Minimal mode --------------------------------------------------------------------------------
const config = ConfigCollection.fromValues(MINIMAL_PAYLOAD);
const result = config.getBoolean('my_config');

if (result.error === ConfigError.NotFound) {
	console.log(
		"The configuration 'my_config' does not exist, or it is set to 'false' and was not sent",
	);
}

## Feature Flag Service base urls

- Production: https://api.atlassian.com/flags
- Staging: https://api.stg.atlassian.com/flags
- Development: https://api.dev.atlassian.com/flags