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