AngularJS/JS如何访问我的函数之外的变量？

Question

我试图访问从功能块内定义的变量np;然而，当我拨打this.items.push(plumbers)时，我遇到了一些问题。我得到TypeError: Cannot call method push of undefined

myApp.factory('np', function($resource, nearbyPlumbers){ 
    var np = function(){ 
    this.items = []; 
    this.busy = false; 
    this.limit = 5; 
    this.offset = 0; 
    }; 

    np.prototype.nextPage = function(){ 
    if (this.busy) return; 
    this.busy = true; 

    var temp; 

    nearbyPlumbers.nearby({lat: -37.746129599999996, lng: 144.9119861}, function(data){ 
     angular.forEach(data, function(plumber){ 
     alert('yay'); 
     //this.items.push(plumber); 
     console.log(plumber); 
     console.log(this.items); // <--- This wont work. How do I access this.items 
     }); 
    }); 
    }; 
    return np; 
}); 

Answer 1

np.prototype.nextPage = function() { 
    if (this.busy) return; 
    this.busy = true; 

    var temp; 
    var that = this; // add this line 

    nearbyPlumbers.nearby({ 
     lat: -37.746129599999996, 
     lng: 144.9119861 
    }, function (data) { 
     angular.forEach(data, function (plumber) { 
      that.items.push(plumber); //access using "that" 
      console.log(plumber); 
      console.log(that.items); 
     }); 
    }); 
}; 

Answer 2

我真的很好奇，为什么你正在使用this，因为这将是根据什么范围不同this访问来自单身。这将解释你得到的错误。

我强烈建议您阅读Angular的工厂，然后再看看代码。 services docs are a good place to start和this question也不错。