auto.$injector.annotate()

Returns an array of service names which the function is requesting for injection. This API is used by the injector to determine which services need to be injected into the function when the function is invoked. There are three ways in which the function can be annotated with the needed dependencies.

Argument names

The simplest form is to extract the dependencies from the arguments of the function. This is done by converting the function into a string using toString() method and extracting the argument names.

// Given
function MyController($scope, $route) {
  // ...
}

// Then
expect(injector.annotate(MyController)).toEqual(['$scope', '$route']);

You can disallow this method by using strict injection mode.

This method does not work with code minification / obfuscation. For this reason the following annotation strategies are supported.

The $inject property

If a function has an $inject property and its value is an array of strings, then the strings represent names of services to be injected into the function.

// Given
var MyController = function(obfuscatedScope, obfuscatedRoute) {
  // ...
}
// Define function dependencies
MyController['$inject'] = ['$scope', '$route'];

// Then
expect(injector.annotate(MyController)).toEqual(['$scope', '$route']);

The array notation

It is often desirable to inline Injected functions and that's when setting the $inject property is very inconvenient. In these situations using the array notation to specify the dependencies in a way that survives minification is a better choice:

// We wish to write this (not minification / obfuscation safe)
injector.invoke(function($compile, $rootScope) {
  // ...
});

// We are forced to write break inlining
var tmpFn = function(obfuscatedCompile, obfuscatedRootScope) {
  // ...
};
tmpFn.$inject = ['$compile', '$rootScope'];
injector.invoke(tmpFn);

// To better support inline function the inline annotation is supported
injector.invoke(['$compile', '$rootScope', function(obfCompile, obfRootScope) {
  // ...
}]);

// Therefore
expect(injector.annotate(
   ['$compile', '$rootScope', function(obfus_$compile, obfus_$rootScope) {}])
 ).toEqual(['$compile', '$rootScope']);