在js中如何实现函数去抖（详细教程）

.factory('debounce', ['$timeout','$q', function($timeout, $q) {
 // The service is actually this function, which we call with the func
 // that should be debounced and how long to wait in between calls
 return function debounce(func, wait, immediate) {
 var timeout;
 // Create a deferred object that will be resolved when we need to
 // actually call the func
 var deferred = $q.defer();
 return function() {
 var context = this, args = arguments;
 var later = function() {
 timeout = null;
 if(!immediate) {
 deferred.resolve(func.apply(context, args));
 deferred = $q.defer();
 }
 };
 var callNow = immediate && !timeout;
 if ( timeout ) {
 $timeout.cancel(timeout);
 }
 timeout = $timeout(later, wait);
 if (callNow) {
 deferred.resolve(func.apply(context,args));
 deferred = $q.defer();
 }
 return deferred.promise;
 };
 };
 }])

$scope.$watch('searchText',debounce(function (newV, oldV) {
 console.log(newV, oldV);
 if (newV !== oldV) {
 $scope.getDatas(newV);
 }
}, 350));

export function debounce(func, delay) {
 let timer

 return function (...args) {
 if (timer) {
 clearTimeout(timer)
 }
 timer = setTimeout(() => {
 func.apply(this, args)
 }, delay)
 }
}

created() {
 this.$watch('searchText', debounce((newSearchText) => {
 this.getDatas(newSearchText)
 }, 200))
}