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- var restArguments = require('./restArguments.js');
- var now = require('./now.js');
- // When a sequence of calls of the returned function ends, the argument
- // function is triggered. The end of a sequence is defined by the `wait`
- // parameter. If `immediate` is passed, the argument function will be
- // triggered at the beginning of the sequence instead of at the end.
- function debounce(func, wait, immediate) {
- var timeout, previous, args, result, context;
- var later = function() {
- var passed = now() - previous;
- if (wait > passed) {
- timeout = setTimeout(later, wait - passed);
- } else {
- timeout = null;
- if (!immediate) result = func.apply(context, args);
- // This check is needed because `func` can recursively invoke `debounced`.
- if (!timeout) args = context = null;
- }
- };
- var debounced = restArguments(function(_args) {
- context = this;
- args = _args;
- previous = now();
- if (!timeout) {
- timeout = setTimeout(later, wait);
- if (immediate) result = func.apply(context, args);
- }
- return result;
- });
- debounced.cancel = function() {
- clearTimeout(timeout);
- timeout = args = context = null;
- };
- return debounced;
- }
- module.exports = debounce;
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