@automattic/calypso-config

Config

This library can be used for managing server- and client-side configs.

All configs are stored in .json files (see examples in sample-config) in a config folder in your working directory. This path can be overridden via the CALYPSO_CONFIG_PATH environment variable.

At boot-up time, the server decides which config file to use based on the NODE_ENV environment variable. The default value is development. For values shared across environments, add them to the _shared.json file. Local-only values can be added via a {environment}.local.json file (e.g. development.local.json).

The entire configuration is available on the server-side and certain keys can be exposed to the client.

Server-side Usage

Config values can be retrieved by invoking the config() exported function with the desired key name:

import config from '@automattic/calypso-config';
console.log( config( 'redirect_uri' ) );

Client-side Usage

To access config values on the client-side, add the property name to the client.json file, which is whitelist of config properties that will be exposed to the client.

A global configData object must also be output during the initial render. Here's an example using React:

import { clientData } from '@automattic/calypso-config';

class Document extends React.Component {
	render() {
		return (
			// ...

			<script
				type="text/javascript"
				dangerouslySetInnerHTML={ {
					__html: `var configData = ${ JSON.stringify( clientData ) };`
				} }
			/>

			// ...
		)
	}
}

Feature Flags

The config files contain a features object that can be used to determine whether to enable a feature for certain environments. This allows us to merge in-progress features without launching them to production. The config module adds a method to detect this: config.isEnabled(). Please make sure to add new feature flags alphabetically so they are easy to find.

{
	"features": {
		"manage/posts": true,
		"reader": true
	}
}

Testing Feature Flags Locally

If you want to temporarily enable/disable some feature flags for a given build, you can do so by setting the ENABLE_FEATURES and/or DISABLE_FEATURES environment variables. Set them to a comma separated list of features you want to enable/disable, respectively:

ENABLE_FEATURES=manage/plugins/compatibility-warning DISABLE_FEATURES=code-splitting,reader npm start

Testing Feature Flags via URLs

If you want to temporarily enable/disable some feature flags you can add a ?flags= query parameter to the URL.

Note that this only works on development, staging, and calypso.live, not in production (this functionality is not suitable for public use on *.wordpress.com).

• ?flags=foo enables feature foo.
• ?flags=-bar disables feature bar.
• ?flags=foo,-bar enables feature foo and disables feature bar.

E.g. http://calypso.localhost:3000/?flags=manage/plugins/compatibility-warning