Warning

Utility for warning messages to the console based on a passed condition.

Installation

Install the module

npm install @wordpress/warning --save

This package assumes that your code will run in an ES2015+ environment. If you're using an environment that has limited or no support for ES2015+ such as lower versions of IE then using core-js or @babel/polyfill will add support for these methods. Learn more about it in Babel docs.

Reducing bundle size

Literal strings aren't minified. Keeping them in your production bundle may increase the bundle size significantly.

To prevent that, you should:

1. Put @wordpress/warning/babel-plugin into your babel config or use @wordpress/babel-preset-default, which already includes the babel plugin.

   This will make sure your warning calls are wrapped within a condition that checks if process.env.NODE_ENV !== 'production'.

2. Use UglifyJS, Terser or any other JavaScript parser that performs dead code elimination. This is usually used in conjunction with JavaScript bundlers, such as webpack.

   When parsing the code in production mode, the warning call will be removed altogether.

API

# default

Shows a warning with message if environment is not production.

Usage

import warning from '@wordpress/warning';

function MyComponent( props ) {
  if ( ! props.title ) {
    warning( '`props.title` was not passed' );
  }
  ...
}

Parameters

• message string: Message to show in the warning.