Javascript JS如何为即时搜索添加延迟？

我的Html表单看起来像

    <form class="navbar-form navbar-left" role="search" name="userName">
      <div class="form-group">
        <input type="text" class="form-control" placeholder="Search Git By Username" ng-model="user" ng-change="searchForUser()" autofocus>
      </div>
    </form>

---

我知道我可以使用ng model options=“{debounce:300}”，但我被要求学习$timeout以及如何在用户仍在键入时取消该事件。GitHub有一个速率限制，如果用户键入的速度太快，GitHub将返回http 403错误。下面是一种处理超时的方法

app.controller('MainCtrl', function ($scope, $timeout, $http) {
    //keep a variable for storing timeoutPromise
    var timeoutPromise;

    $scope.searchForUser = function () {
        $scope.selectedUser = null;
        $scope.selectedRepo = null;
        $scope.returnedRepos = [];
        $scope.returnedCommits = [];

        if ($scope.user.length === 0) {
            $scope.returnedUsers = null;
            return;
        }

        //if already a timeout is in progress cancel it
        if (timeoutPromise) {
            $timeout.cancel(timeoutPromise);
        }

        //Make a fresh timeout
        timeoutPromise = $timeout(searchUsers, 500)
                         .finally(function(){
                             timeoutPromise = null; //nullify it
                          });

    };

    function searchUsers() {
        $http.get("https://api.github.com/search/users?q=" + $scope.user).
        success(function (data, status) {
            if (status === 200) {
                $scope.returnedUsers = data.items;
            }
        }).
        error(function (data, status) {
            alert("something happened with quhhnnhhhh");
        });

    }
});

---

我也会使用我，但我必须使用$timeout

app.controller('MainCtrl', function ($scope, $timeout, $http) {
    //keep a variable for storing timeoutPromise
    var timeoutPromise;

    $scope.searchForUser = function () {
        $scope.selectedUser = null;
        $scope.selectedRepo = null;
        $scope.returnedRepos = [];
        $scope.returnedCommits = [];

        if ($scope.user.length === 0) {
            $scope.returnedUsers = null;
            return;
        }

        //if already a timeout is in progress cancel it
        if (timeoutPromise) {
            $timeout.cancel(timeoutPromise);
        }

        //Make a fresh timeout
        timeoutPromise = $timeout(searchUsers, 500)
                         .finally(function(){
                             timeoutPromise = null; //nullify it
                          });

    };

    function searchUsers() {
        $http.get("https://api.github.com/search/users?q=" + $scope.user).
        success(function (data, status) {
            if (status === 200) {
                $scope.returnedUsers = data.items;
            }
        }).
        error(function (data, status) {
            alert("something happened with quhhnnhhhh");
        });

    }
});