Property 'value' does not exist on type EventTarget in TypeScript
So the following code is in Angular 4 and I can't figure out why it doesn't work the way as expected.
Here is a snippet of my handler:
onUpdatingServerName(event: Event) {
console.log(event);
this.newserverName = event.target.value; //this wont work
}
HTML element:
<input type="text" class="form-control" (input)="onUpdatingServerName($event)">
The code gives me the error:
Property 'value' does not exist on type 'EventTarget'.
But as it can be seen in the console.log
that value does exist on the event.target
.
Solution 1:
event.target
here is an HTMLElement
which is the parent of all HTML elements, but isn't guaranteed to have the property value
. TypeScript detects this and throws the error. Cast event.target
to the appropriate HTML element to ensure it is HTMLInputElement
which does have a value
property:
(<HTMLInputElement>event.target).value
Per the documentation:
Type the
$event
The example above casts the
$event
as anany
type. That simplifies the code at a cost. There is no type information that could reveal properties of the event object and prevent silly mistakes.[...]
The
$event
is now a specificKeyboardEvent
. Not all elements have avalue
property so it caststarget
to an input element.
(Emphasis mine)
Solution 2:
Passing HTMLInputElement as a generic to the event type should work too:
onUpdatingServerName(event: React.ChangeEvent<HTMLInputElement>) {
console.log(event);
this.newserverName = event.target.value;
}