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Dieses Dokument verwendet PHP-Handbuch für chinesische Websites Freigeben
$injector is used to retrieve object instances as defined by
Provider, instantiate types, invoke methods,
and load modules.
The following always holds true:
var $injector = angular.injector();
expect($injector.get('$injector')).toBe($injector);
expect($injector.invoke(Function($injector){
return $injector;
}).toBe($injector);JavaScript does not have annotations, and annotations are needed for 依赖注入. The following are all valid ways of annotating function with injection arguments and are equivalent.
// inferred (only works if code not minified/obfuscated)
$injector.invoke(Function(serviceA){});
// annotated
Function explicit(serviceA) {};
explicit.$inject = ['serviceA'];
$injector.invoke(explicit);
// inline
$injector.invoke(['serviceA', Function(serviceA){}]);In JavaScript calling toString() on a function returns the function definition. The definition
can then be parsed and the function arguments can be extracted. 注意： This does not work with
minification, and obfuscation tools since these tools change the argument names.
$inject AnnotationBy adding an $inject property onto a function the injection parameters can be specified.
As an array of injection names, where the last item in the array is the function to call.
$injector();
get(名称);
Return an instance of the service.
| 参数 | 类型 | 详述 |
|---|---|---|
| name | string |
The name of the instance to retrieve. |
| * |
The instance. |
invoke(fn, [self], [locals]);
Invoke the method and supply the method arguments from the $injector.
| 参数 | 类型 | 详述 |
|---|---|---|
| fn | !Function |
The function to invoke. Function parameters are injected according to the $inject Annotation rules. |
|
self
(可选)
|
Object |
The |
|
locals
(可选)
|
Object |
Optional object. If preset then any argument names are read from this
object first, before the |
| * |
the value returned by the invoked |
has(名称);
Allows the user to query if the particular service exists.
| 参数 | 类型 | 详述 |
|---|---|---|
| Name | string |
of the service to query. |
| boolean |
returns true if injector has given service. |
instantiate(Type, [locals]);
Create a new instance of JS type. The method takes a constructor function, invokes the new operator, and supplies all of the arguments to the constructor function as specified by the constructor annotation.
| 参数 | 类型 | 详述 |
|---|---|---|
| Type | Function |
Annotated constructor function. |
|
locals
(可选)
|
Object |
Optional object. If preset then any argument names are read from this
object first, before the |
| Object |
new instance of |
annotate(fn);
Returns an array of service names which the function is requesting for injection. This API is used by the injector to determine which services need to be injected into the function when the function is invoked. There are three ways in which the function can be annotated with the needed dependencies.
The simplest form is to extract the dependencies from the arguments of the function. This is done
by converting the function into a string using toString() method and extracting the argument
names.
// Given
Function MyController($scope, $route) {
// ...
}
// Then
expect(injector.annotate(MyController)).toEqual(['$scope', '$route']);This method does not work with code minification / obfuscation. For this reason the following annotation strategies are supported.
$inject propertyIf 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']);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']);| 参数 | 类型 | 详述 |
|---|---|---|
| fn | function()Array.<(string|function())> |
Function for which dependent service names need to be retrieved as described above. |
| Array.<string> |
The names of the services which the function requires. |