什么是类型友好注射? [英] What is the type friendly injection?

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问题描述

在 AngularJS文档中，对工厂和服务之间的差异进行了解释. ，值，常量和提供者.

In the AngularJS documentation, there is an explanation of the differences between a factory, a service, a value, a constant and a provider .

最后，我们有一个比较表: 其中一行是类型友好注入".我不明白那是什么.

At the end, we have a comparison table: One of the rows is "type friendly injection". I could not understand what it is.

那是什么意思?另外，为了使值具有此类型友好的注入"，这意味着直接使用新的运算符来进行初始化"是什么意思?

What does that mean? Additionally, what does it mean that, in order that a value will have this "type friendly injection", is at the cost of "eager initialization by using new operator directly"?

推荐答案

在AngularJS中，您可以通过多种方式注入依赖项:

In AngularJS, you can inject dependencies in multiple ways:

在指令link中按位置的功能
在指令定义中按名称
在控制器功能中按名称
在工厂功能中按名称
在服务功能中按类型

in the directive link function by position
in the directive definition by name
in the controller function by name
in the factory function by name
in the service function by type

类型友好注入允许您通过引用隐式调用构造函数:

Type friendly injection allows you to implicity invoke a constructor function by reference:

myApp.service('Pattern', ["Infinity", RegExp]);

，而不是通过使用new关键字来明确声明:

rather than by explicity using the new keyword:

myApp.factory('Pattern', 
 ["Infinity", function(Infinity) 
  {
  return new RegExp(Infinity);
  } 
 ]);

function goInfinity(Infinity)
  {
  return new RegExp(Infinity);
  } 

goInfinity.$inject = ["Infinity"];
myApp.factory('Pattern', goInfinity);

服务"配方产生的服务类似于值"或工厂"配方，但是它是通过使用new运算符调用构造函数来实现的.构造函数可以接受零个或多个参数，这些参数表示此类型的实例所需的依赖项.

The Service recipe produces a service just like the Value or Factory recipes, but it does so by invoking a constructor with the new operator. The constructor can take zero or more arguments, which represent dependencies needed by the instance of this type.

急切的初始化意味着constant配方必须返回构造函数才能使用上述语法:

Eager initialization means that a constant recipe must return a constructor in order to use the aforementioned syntax:

function RegExpConstant() 
  {
  return new RegExp(Infinity);
  } 

myApp.constant('Pattern', RegExpConstant)

而不是返回函数，对象或文字值.

rather than returning a function, object, or literal value.

术语来自Java:

服务是一组著名的接口. 服务提供者是服务的特定实现. 工厂是一个对象，它返回对另一个对象的对象引用

A service is a well-known set of interfaces. A service provider is a specific implementation of a service. A factory is an object that returns an object reference to another object

参考