By default, the value and validation status of a `FormControl` updates
whenever its value changes. If an application has heavy validation
requirements, updating on every text change can sometimes be too expensive.
This commit introduces a new option that improves performance by delaying
form control updates until the "blur" event. To use it, set the `updateOn`
option to `blur` when instantiating the `FormControl`.
```ts
// example without validators
const c = new FormControl(, { updateOn: blur });
// example with validators
const c= new FormControl(, {
validators: Validators.required,
updateOn: blur
});
```
Like in AngularJS, setting `updateOn` to `blur` will delay the update of
the value as well as the validation status. Updating value and validity
together keeps the system easy to reason about, as the two will always be
in sync. It's also worth noting that the value/validation pipeline does
still run when the form is initialized (in order to support initial values).
Closes#7113
This is possibly a temporary fix for the layout, until we decide whether we want
to remove the guide or properly add it to the SideNav menu.
Fixes#17912
The Internationalisation documentation, "Translate text nodes" section, has an incomplete
markdown anchor, and leaks markdown into the page. Fix the anchor by adding the opening bracket.
The static reflectory check for macro function recursion was too
agressive and disallowed calling a function with argument that also
calls the same function. For example, it disallowed nested animation
groups.
Fixes: #17467
FormControls, FormGroups, and FormArrays now optionally accept an options
object as their second argument. Validators and async validators can be
passed in as part of this options object (though they can still be passed
in as the second and third arg as before).
```ts
const c = new FormControl(, {
validators: [Validators.required],
asyncValidators: [myAsyncValidator]
});
```
This commit also adds support for passing arrays of validators and async
validators to FormGroups and FormArrays, which formerly only accepted
individual functions.
```ts
const g = new FormGroup({
one: new FormControl()
}, [myPasswordValidator, myOtherValidator]);
```
This change paves the way for adding more options to AbstractControls,
such as more fine-grained control of validation timing.
