| /** |
| * Lo-Dash 2.4.1 (Custom Build) <http://lodash.com/> |
| * Build: `lodash modularize modern exports="node" -o ./modern/` |
| * Copyright 2012-2013 The Dojo Foundation <http://dojofoundation.org/> |
| * Based on Underscore.js 1.5.2 <http://underscorejs.org/LICENSE> |
| * Copyright 2009-2013 Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors |
| * Available under MIT license <http://lodash.com/license> |
| */ |
| var debounce = require('./debounce'), |
| isFunction = require('../objects/isFunction'), |
| isObject = require('../objects/isObject'); |
| |
| /** Used as an internal `_.debounce` options object */ |
| var debounceOptions = { |
| 'leading': false, |
| 'maxWait': 0, |
| 'trailing': false |
| }; |
| |
| /** |
| * Creates a function that, when executed, will only call the `func` function |
| * at most once per every `wait` milliseconds. Provide an options object to |
| * indicate that `func` should be invoked on the leading and/or trailing edge |
| * of the `wait` timeout. Subsequent calls to the throttled function will |
| * return the result of the last `func` call. |
| * |
| * Note: If `leading` and `trailing` options are `true` `func` will be called |
| * on the trailing edge of the timeout only if the the throttled function is |
| * invoked more than once during the `wait` timeout. |
| * |
| * @static |
| * @memberOf _ |
| * @category Functions |
| * @param {Function} func The function to throttle. |
| * @param {number} wait The number of milliseconds to throttle executions to. |
| * @param {Object} [options] The options object. |
| * @param {boolean} [options.leading=true] Specify execution on the leading edge of the timeout. |
| * @param {boolean} [options.trailing=true] Specify execution on the trailing edge of the timeout. |
| * @returns {Function} Returns the new throttled function. |
| * @example |
| * |
| * // avoid excessively updating the position while scrolling |
| * var throttled = _.throttle(updatePosition, 100); |
| * jQuery(window).on('scroll', throttled); |
| * |
| * // execute `renewToken` when the click event is fired, but not more than once every 5 minutes |
| * jQuery('.interactive').on('click', _.throttle(renewToken, 300000, { |
| * 'trailing': false |
| * })); |
| */ |
| function throttle(func, wait, options) { |
| var leading = true, |
| trailing = true; |
| |
| if (!isFunction(func)) { |
| throw new TypeError; |
| } |
| if (options === false) { |
| leading = false; |
| } else if (isObject(options)) { |
| leading = 'leading' in options ? options.leading : leading; |
| trailing = 'trailing' in options ? options.trailing : trailing; |
| } |
| debounceOptions.leading = leading; |
| debounceOptions.maxWait = wait; |
| debounceOptions.trailing = trailing; |
| |
| return debounce(func, wait, debounceOptions); |
| } |
| |
| module.exports = throttle; |