Proyectos de Subversion Moodle

// This file is part of Moodle - http://moodle.org/

//

// Moodle is free software: you can redistribute it and/or modify

// it under the terms of the GNU General Public License as published by

// the Free Software Foundation, either version 3 of the License, or

// (at your option) any later version.

//

// Moodle is distributed in the hope that it will be useful,

// but WITHOUT ANY WARRANTY; without even the implied warranty of

// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

// GNU General Public License for more details.

//

// You should have received a copy of the GNU General Public License

// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.

/**

 * Utility functions.

 *

 * @module core/utils

 * @copyright  2019 Ryan Wyllie <ryan@moodle.com>

 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

 */

import Pending from 'core/pending';

import jQuery from 'jquery';

 /**

  * Create a wrapper function to throttle the execution of the given

  *

  * function to at most once every specified period.

  *

  * If the function is attempted to be executed while it's in cooldown

  * (during the wait period) then it'll immediately execute again as

  * soon as the cooldown is over.

  *

  * @method

  * @param {Function} func The function to throttle

  * @param {Number} wait The number of milliseconds to wait between executions

  * @return {Function}

  */

export const throttle = (func, wait) => {

    let onCooldown = false;

    let runAgain = null;

    const run = function(...args) {

        if (runAgain === null) {

            // This is the first time the function has been called.

            runAgain = false;

        } else {

            // This function has been called a second time during the wait period

            // so re-run it once the wait period is over.

            runAgain = true;

        }

        if (onCooldown) {

            // Function has already run for this wait period.

            return;

        }

        func.apply(this, args);

        onCooldown = true;

        setTimeout(() => {

            const recurse = runAgain;

            onCooldown = false;

            runAgain = null;

            if (recurse) {

                run(args);

            }

        }, wait);

    };

    return run;

};

/**

 * @property {Map} debounceMap A map of functions to their debounced pending promises.

 */

const debounceMap = new Map();

/**

 * Create a wrapper function to debounce the execution of the given

 * function. Each attempt to execute the function will reset the cooldown

 * period.

 *

 * @method

 * @param {Function} func The function to debounce

 * @param {Number} wait The number of milliseconds to wait after the final attempt to execute

 * @param {Object} [options]

 * @param {boolean} [options.pending=false] Whether to wrap the debounced method in a pending promise

 * @param {boolean} [options.cancel=false] Whether to add a cancel method to the debounced function

 * @return {Function}

 */

export const debounce = (

    func,

    wait,

    {

        pending = false,

        cancel = false,

    } = {},

) => {

    let timeout = null;

    const returnedFunction = (...args) => {

        if (pending && !debounceMap.has(returnedFunction)) {

            debounceMap.set(returnedFunction, new Pending('core/utils:debounce'));

        }

        clearTimeout(timeout);

        timeout = setTimeout(async () => {

            // Get the current pending promise and immediately empty it.

            // This is important to allow the function to be debounced again as soon as possible.

            // We do not resolve it until later - but that's fine because the promise is appropriately scoped.

            const pendingPromise = debounceMap.get(returnedFunction);

            debounceMap.delete(returnedFunction);

            // Allow the debounced function to return a Promise.

            // This ensures that Behat will not continue until the function has finished executing.

            await func.apply(this, args);

            // Resolve the pending promise if it exists.

            pendingPromise?.resolve();

        }, wait);

    };

    if (cancel) {

        returnedFunction.cancel = () => {

            const pendingPromise = debounceMap.get(returnedFunction);

            pendingPromise?.resolve();

            clearTimeout(timeout);

        };

    }

    return returnedFunction;

};

/**

 * Normalise the provided component such that '', 'moodle', and 'core' are treated consistently.

 *

 * @param   {String} component

 * @returns {String}

 */

export const getNormalisedComponent = (component) => {

    if (component) {

        if (component !== 'moodle' && component !== 'core') {

            return component;

        }

    }

    return 'core';

};

/**

 * Wrap a Native Promise in a jQuery Whenable for b/c.

 *

 * @param {*} promise

 * @returns {jQuery}

 */

export const wrapPromiseInWhenable = (promise) => jQuery.when(promise);