Question

i am leaning how to use underscore in AngularJS. i try to extract last 2 element from array and show in alert. code is working but the problem is last two element is showing together in alert but i want to show each element in alert one after one. here is my code. please tell me what i should use as a result each last 2 element in alter one after one.

<div ng-app="myApp" ng-controller="MainCtrl">

</div>

var myApp = angular.module('myApp', []);

myApp.factory('_', function() {
  return window._; //Underscore should be loaded on the page
});

myApp.controller('MainCtrl', function ($scope, _) {
    $scope.awesomeThings = [
      'HTML5 Boilerplate',
      'AngularJS2',
      'AngularJS1'
    ];

    var x = _.last($scope.awesomeThings, 2);
        //alert(x[0]);

        _.each([x],function(i)
    {
        alert(i);
    });

  });

i also follow these links

how to break the _.each function in underscore.js

how to install underscore.js in my angular application?

Plucking an Object in an array using underscore.js

Answer 1

_.last(..., 2)会返回一个包含2个项目的数组。

var x = _.last($scope.awesomeThings, 2);

_.each遍历数组，所以：

_.each([x], function(i) {

注意你是如何不必要地将x包装在另一个数组中的。它成功遍历数组中唯一的项，这是另一个包含所需数据的数组。

您的解决方案应该简单：

_.each(x, function(i) {
  alert(i);
});

或者更简单，就像你已经注意到你可以这样做：

_.each(x, alert);

Answer 2

我找到了我正在寻找的解决方案。

这两行解决了我的问题

var x = _.last($scope.awesomeThings, 2);
_.each(x.reverse(), alert);

完整代码示例

var myApp = angular.module('myApp', []);

myApp.factory('_', function() {
  return window._; //Underscore should be loaded on the page
});


myApp.controller('MainCtrl', function ($scope, _) {
    $scope.awesomeThings = [
      'HTML5 Boilerplate',
      'AngularJS2',
      'AngularJS1'
    ];
    //alert('pp');
    /*_.each([1,2,3],function(i)
    {
        alert(i);
    });*/
    var x = _.last($scope.awesomeThings, 2);
    _.each(x.reverse(), alert);
        //alert(x[0]);

        /*_.each([x],function(i)
    {
        alert(i);
    });*/

  });

AngularJS and underscore usage in same example

2 个答案:

完整代码示例