71 lines
1.8 KiB
JavaScript
71 lines
1.8 KiB
JavaScript
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/**
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* Returns a function, that, as long as it continues to be invoked, will not
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* be triggered. The function will be called after it stops being called for
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* N milliseconds. If `immediate` is passed, trigger the function on the
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* leading edge, instead of the trailing. The function also has a property 'clear'
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* that is a function which will clear the timer to prevent previously scheduled executions.
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*
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* @source underscore.js
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* @see http://unscriptable.com/2009/03/20/debouncing-javascript-methods/
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* @param {Function} function to wrap
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* @param {Number} timeout in ms (`100`)
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* @param {Boolean} whether to execute at the beginning (`false`)
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* @api public
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*/
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function debounce(func, wait, immediate){
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var timeout, args, context, timestamp, result;
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if (null == wait) wait = 100;
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function later() {
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var last = Date.now() - timestamp;
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if (last < wait && last >= 0) {
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timeout = setTimeout(later, wait - last);
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} else {
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timeout = null;
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if (!immediate) {
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result = func.apply(context, args);
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context = args = null;
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}
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}
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};
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var debounced = function(){
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context = this;
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args = arguments;
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timestamp = Date.now();
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var callNow = immediate && !timeout;
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if (!timeout) timeout = setTimeout(later, wait);
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if (callNow) {
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result = func.apply(context, args);
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context = args = null;
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}
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return result;
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};
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debounced.clear = function() {
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if (timeout) {
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clearTimeout(timeout);
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timeout = null;
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}
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};
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debounced.flush = function() {
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if (timeout) {
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result = func.apply(context, args);
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context = args = null;
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clearTimeout(timeout);
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timeout = null;
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}
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};
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return debounced;
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};
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// Adds compatibility for ES modules
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debounce.debounce = debounce;
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module.exports = debounce;
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