在 AngularJS 测试中，在_servicename_中下划线是什么意思？

在下面的示例测试中，原始的提供程序名称是 APIEndpointProvider，但是对于注入和服务实例化，约定似乎是必须用下划线包装它。为什么？

'use strict';


describe('Provider: APIEndpointProvider', function () {


beforeEach(module('myApp.providers'));


var APIEndpointProvider;
beforeEach(inject(function(_APIEndpointProvider_) {
APIEndpointProvider = _APIEndpointProvider_;
}));


it('should do something', function () {
expect(!!APIEndpointProvider).toBe(true);
});


});

我错过了什么更好的解释？

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最佳答案

The underscores are a convenience trick we can use to inject a service under a different name so that we can locally assign a local variable of the same name as the service.

That is, if we couldn't do this, we'd have to use some other name for a service locally:

beforeEach(inject(function(APIEndpointProvider) {
AEP = APIEndpointProvider; // <-- we can't use the same name!
}));


it('should do something', function () {
expect(!!AEP).toBe(true);  // <-- this is more confusing
});

The $injector used in testing is able to just remove the underscores to give us the module we want. It doesn't do anything except let us reuse the same name.