数据绑定控制器 - 服务：为工作对象，但不换号 [英] Data binding Controller-Service: works for objects but not for numbers

问题描述

为什么在 json_var 同步为 INT 而不是为 INT数据？

Why are the data synced for the int in json_var and not for the int?

myService.json_var 当 $ scope.json_var 更改进行更新。
myService.int_var 不更新时， $ scope.int_var 的变化。

myService.json_var is updated when $scope.json_var changes. myService.int_var is not updated when $scope.int_var changes.

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

myApp.factory('myService', [
  function() {
     return {
        json_var : {val:17},
        int_var : 36
     }

     }
  ]);


myApp.controller('myCtrl', [ '$scope',  'myService', 
  function ($scope, myService)
  {
     $scope.json_var = myService.json_var; // doing this myService.json_var is updated when $scope.json_var changes
     $scope.int_var = myService.int_var; // no sync for int

     $scope.deb = function()
     {
        console.log($scope.int_var);
        console.log( myService.int_var);

        console.log($scope.json_var.val);
        console.log( myService.json_var.val);
     }
  }
] );

https://gist.github.com/SebSept/8ddcaad130ef9c091bd0

推荐答案

在JavaScript中，复合类型（对象，数组）按引用传递（参考副本，是precise）和原语（字符串，数字，布尔值）是按值传递。

In JavaScript, composite types (objects, arrays) are passed by reference (copy of a reference, to be precise), and primitives (strings, numbers, booleans) are passed by value.

36 是一种原始。
当你通过从​​你的服务原语（ myService.int_var ）到您的控制器（ $ scope.int_var ）的 36 是按值传递。当您更改 $ scope.int_var 到 42 的 myService.int_var 变量将不会反映这种变化（这是每个语言设计）。

36 is a primitive. When you pass your primitive from your service (myService.int_var) into your controller ($scope.int_var) the 36 is passed by value. When you change $scope.int_var to 42 the myService.int_var variable will not reflect the change (this is per language design).

在另一方面， myService.json_var 是一个复合材料。当你通过 myService.json_var 到 $ scope.json_var ，到为myService的参考。 json_var 对象是以值到 $ scope.json_var 变量传递。当您更改变量中的东西（例如，如果你改变 json_var.val 到 18 ）的变化将反映在 myService.json_var 对象内为好，这样 myService.json_var.val 将等于 18 以及

On the other hand, myService.json_var is a composite. When you pass myService.json_var to $scope.json_var, a reference to the myService.json_var object is passed by value to the $scope.json_var variable. When you change something inside that variable (e.g. if you change json_var.val to 18), the change will be reflected inside the myService.json_var object as well, so myService.json_var.val will equal 18 as well.

TL;博士确保总有一个点。某个地方，当你身边路过的东西角。

tl;dr Make sure there's always a dot "." somewhere when you're passing things around in Angular.

这篇关于数据绑定控制器 - 服务：为工作对象，但不换号的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！