angularjs - 要求 $scope 来欺骗 BC Controller 模块

Question

在指令 ngSwitch 和 FromController 的源代码中你可以看到这样的注释:

// asks for $scope to fool the BC controller module

这是什么作弊行为？为什么使用它？

ngSwitch Source Line

    // asks for $scope to fool the BC controller module
    controller: ['$scope', function ngSwitchController() {
     this.cases = {};
    }] ...

FormController Soruce Line

//asks for $scope to fool the BC controller module
FormController.$inject = ['$element', '$attrs', '$scope', '$animate'];
function FormController(element, attrs, $scope, $animate) {  ...

Answer 1

BC controller module是 Backward Compatibility 的简写。

Load this module to enable old-style controllers, where controller and scope are mixed together.

This module decorates Angular's $controller service:

• if given controller does not ask for $scope, it instantiates it in old-way

• if given controller does ask for $scope, instantiation is delegated to default $controller service.

  This also allows migrating apps step by step.

因此，默认的 Angular 模块总是要求 $scope 引用，即使它们不打算使用它，以避免为 BC 实例化。