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exported from angular2/di
defined in angular2/src/di/injector.ts (line 27)
:markdown
A dependency injection container used for resolving dependencies.
An `Injector` is a replacement for a `new` operator, which can automatically resolve the
constructor dependencies.
In typical use, application code asks for the dependencies in the constructor and they are
resolved by the `Injector`.
## Example:
Suppose that we want to inject an `Engine` into class `Car`, we would define it like this:
```javascript
class Engine {
}
class Car {
constructor(@Inject(Engine) engine) {
}
}
```
Next we need to write the code that creates and instantiates the `Injector`. We then ask for the
`root` object, `Car`, so that the `Injector` can recursively build all of that object's
dependencies.
```javascript
main() {
var injector = Injector.resolveAndCreate([Car, Engine]);
// Get a reference to the `root` object, which will recursively instantiate the tree.
var car = injector.get(Car);
}
```
Notice that we don't use the `new` operator because we explicitly want to have the `Injector`
resolve all of the object's dependencies automatically.
.l-main-section
h2 Members
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h3 constructor
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code.
constructor(bindings: List<ResolvedBinding>, parent: Injector, defaultBindings: boolean)
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@param `bindings` A sparse list of ResolvedBinding
s. See `resolve` for the
Injector
.
@param `parent` Parent Injector or `null` if root Injector.
@param `defaultBindings` Setting to true will auto-create bindings. (Only use with root
injector.)
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h3 asyncGet
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asyncGet(token)
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Retrieves an instance from the injector asynchronously. Used with asynchronous bindings.
@param `token`: usually a `Type`. (Same as token used while setting up a binding).
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h3 createChildFromResolved
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createChildFromResolved(bindings: List<ResolvedBinding>)
:markdown
Creates a child injector and loads a new set of ResolvedBinding
s into it.
@param `bindings`: A sparse list of ResolvedBinding
s.
See `resolve` for the Injector
.
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h3 get
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get(token)
:markdown
Retrieves an instance from the injector.
@param `token`: usually the `Type` of an object. (Same as the token used while setting up a
binding).
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h3 getOptional
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getOptional(token)
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Retrieves an instance from the injector.
@param `token`: usually a `Type`. (Same as the token used while setting up a binding).
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h3 parent
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Direct parent of this injector.
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h3 resolveAndCreateChild
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resolveAndCreateChild(bindings: List<Type | Binding | List<any>>)
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Creates a child injector and loads a new set of bindings into it.
A resolution is a process of flattening multiple nested lists and converting individual
bindings into a list of ResolvedBinding
s. The resolution can be cached by `resolve`
for the Injector
for performance-sensitive code.
@param `bindings` can be a list of `Type`, Binding
, ResolvedBinding
, or a
recursive list of more bindings.