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))
}