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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
// Disclaimer: Some of the functions in this module implement APIs from
// Jeremy Ashkenas's http://underscorejs.org/ library and all credits for
// those goes to him.
"use strict";
module.metadata = {
"stability": "unstable"
};
const { arity, name, derive, invoke } = require("./helpers");
const { setTimeout, clearTimeout, setImmediate } = require("../../timers");
/**
* Takes a function and returns a wrapped one instead, calling which will call
* original function in the next turn of event loop. This is basically utility
* to do `setImmediate(function() { ... })`, with a difference that returned
* function is reused, instead of creating a new one each time. This also allows
* to use this functions as event listeners.
*/
const defer = f => derive(function(...args) {
setImmediate(invoke, f, args, this);
}, f);
exports.defer = defer;
// Exporting `remit` alias as `defer` may conflict with promises.
exports.remit = defer;
/**
* Much like setTimeout, invokes function after wait milliseconds. If you pass
* the optional arguments, they will be forwarded on to the function when it is
* invoked.
*/
const delay = function delay(f, ms, ...args) {
setTimeout(() => f.apply(this, args), ms);
};
exports.delay = delay;
/**
* From underscore's `_.debounce`
* http://underscorejs.org
* (c) 2009-2014 Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
* Underscore may be freely distributed under the MIT license.
*/
const debounce = function debounce (fn, wait) {
let timeout, args, context, timestamp, result;
let later = function () {
let last = Date.now() - timestamp;
if (last < wait) {
timeout = setTimeout(later, wait - last);
} else {
timeout = null;
result = fn.apply(context, args);
context = args = null;
}
};
return function (...aArgs) {
context = this;
args = aArgs;
timestamp = Date.now();
if (!timeout) {
timeout = setTimeout(later, wait);
}
return result;
};
};
exports.debounce = debounce;
/**
* From underscore's `_.throttle`
* http://underscorejs.org
* (c) 2009-2014 Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
* Underscore may be freely distributed under the MIT license.
*/
const throttle = function throttle (func, wait, options) {
let context, args, result;
let timeout = null;
let previous = 0;
options || (options = {});
let later = function() {
previous = options.leading === false ? 0 : Date.now();
timeout = null;
result = func.apply(context, args);
context = args = null;
};
return function() {
let now = Date.now();
if (!previous && options.leading === false) previous = now;
let remaining = wait - (now - previous);
context = this;
args = arguments;
if (remaining <= 0) {
clearTimeout(timeout);
timeout = null;
previous = now;
result = func.apply(context, args);
context = args = null;
} else if (!timeout && options.trailing !== false) {
timeout = setTimeout(later, remaining);
}
return result;
};
};
exports.throttle = throttle;
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