CODEWITHSUNDEEP
angulartypescript
alexania
alexania

Reputation: 2791

Angular 8 typescript number value coming through as string

I'm sure I'm just doing something stupid but I can't see it.

I have the following html:

<input type="number" (change)="changeEventDate(event, dateField.value)" [value]="date" #dateField />

And typescript:

const date: number;

...

changeEventDate(event: Event, date: number) {
  console.log(typeof date); // This logs "string"
}

}

So I'm passing in a number to [value], it's an input of type number and the typescript method takes in a number parameter... how is it still a string?

(I know can just cast it to fix the issue, but I'm trying to understand why it's not working as expected.)

And I guess, in case it's important:

"@angular-devkit/build-angular": "~0.803.20",
"@angular/cli": "~8.3.20",
"@angular/compiler-cli": "~8.2.14",
"@angular/language-service": "~8.2.14",
"typescript": "~3.5.3"

Upvotes: 0

Views: 2443

Answers (2)

Nadhir Falta
Nadhir Falta

Reputation: 5257

By using the dateField.value you will be getting the DOM value, which will always be a string.

There are couple things you can do to make things better, First thing (best thing in Angular) which is two way data binding.

  • make your date variable public and then in your html <input [(ngModel)]="date" ...
  • And in your function console.log(typeof this.date);

Another thing (just a workaround), is to keep your code as is, and just convert the passed in value to a number console.log(typeof Number(date));

Upvotes: 2

Sam
Sam

Reputation: 632

Here you're getting the value from input field dateField.value it returns the string value. You can fix it changing to changeEventDate(event, +dateField.value)

Upvotes: 0

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