@aventum/hooks/src/createRemoveHook.js

A universal, lightweight & efficient EventManager/PluginsSystem/MiddlewareManager/ExtendabilitySystem for JavaScript

/**
 * Internal dependencies
 */
import validateNamespace from './validateNamespace.js';
import validateHookName from './validateHookName.js';
import { doAction } from './';

/**
 * Returns a function which, when invoked, will remove a specified hook or all
 * hooks by the given name.
 *
 * @param  {Object}   hooks      Stored hooks, keyed by hook name.
 * @param  {boolean}     removeAll  Whether to remove all callbacks for a hookName, without regard to namespace. Used to create `removeAll*` functions.
 *
 * @return {Function}            Function that removes hooks.
 */
function createRemoveHook( hooks, removeAll ) {
	/**
	 * Removes the specified callback (or all callbacks) from the hook with a
	 * given hookName and namespace.
	 *
	 * @param {string}    hookName  The name of the hook to modify.
	 * @param {string}    namespace The unique namespace identifying the callback in the form `vendor/plugin/function`.
	 *
	 * @return {number}             The number of callbacks removed.
	 */
	return function removeHook( hookName, namespace ) {
		if ( ! validateHookName( hookName ) ) {
			return;
		}

		if ( ! removeAll && ! validateNamespace( namespace ) ) {
			return;
		}

		// Bail if no hooks exist by this name
		if ( ! hooks[ hookName ] ) {
			return 0;
		}

		let handlersRemoved = 0;

		if ( removeAll ) {
			handlersRemoved = hooks[ hookName ].handlers.length;
			hooks[ hookName ] = {
				runs: hooks[ hookName ].runs,
				handlers: [],
			};
		} else {
			// Try to find the specified callback to remove.
			const handlers = hooks[ hookName ].handlers;
			for ( let i = handlers.length - 1; i >= 0; i-- ) {
				if (
					handlers[ i ].namespace === namespace
				) {
					handlers.splice( i, 1 );
					handlersRemoved++;
					// This callback may also be part of a hook that is
					// currently executing.  If the callback we're removing
					// comes after the current callback, there's no problem;
					// otherwise we need to decrease the execution index of any
					// other runs by 1 to account for the removed element.
					( hooks.__current || [] ).forEach( ( hookInfo ) => {
						if ( hookInfo.name === hookName && hookInfo.currentIndex >= i ) {
							hookInfo.currentIndex--;
						}
					} );
				}
			}
		}
		if ( hookName !== 'hookRemoved' ) {
			doAction( 'hookRemoved', hookName, namespace );
		}

		return handlersRemoved;
	};
}

export default createRemoveHook;