tui-code-snippet/tricks/debounce.js

TOAST UI Utility: CodeSnippet

/**
 * @fileoverview Creates a debounced function that delays invoking fn until after delay milliseconds has elapsed since the last time the debouced function was invoked.
 * @author NHN FE Development Lab <dl_javascript.nhn.com>
 */

'use strict';

/**
 * @module tricks
 */

/**
 * Creates a debounced function that delays invoking fn until after delay milliseconds has elapsed
 * since the last time the debouced function was invoked.
 * @param {function} fn The function to debounce.
 * @param {number} [delay=0] The number of milliseconds to delay
 * @returns {function} debounced function.
 * @memberof module:tricks
 * @example
 * // ES6
 * import debounce from 'tui-code-snippet/tricks/debounce';
 * 
 * // CommonJS
 * const debounce = require('tui-code-snippet/tricks/debounce');
 *
 * function someMethodToInvokeDebounced() {}
 *
 * const debounced = debounce(someMethodToInvokeDebounced, 300);
 *
 * // invoke repeatedly
 * debounced();
 * debounced();
 * debounced();
 * debounced();
 * debounced();
 * debounced();    // last invoke of debounced()
 *
 * // invoke someMethodToInvokeDebounced() after 300 milliseconds.
 */
function debounce(fn, delay) {
  var timer, args;

  /* istanbul ignore next */
  delay = delay || 0;

  function debounced() { // eslint-disable-line require-jsdoc
    args = Array.prototype.slice.call(arguments);

    window.clearTimeout(timer);
    timer = window.setTimeout(function() {
      fn.apply(null, args);
    }, delay);
  }

  return debounced;
}

module.exports = debounce;