Angular passing event data doesn't log correctly

Question

So I have the component favorite for the "add to favorites" functionality.

I have the next code in favorite.component.ts (only lines for emitting event)

 import { Component, OnInit, Input, Output, EventEmitter } from '@angular/core';

 @Input() isFavorite = false;

 this.change.emit({ newValue: this.isFavorite });

I have the next code in app.component.html:

<favorite [isFavorite]="post.isFavorite" (change)="favButtonChanged($event)"></favorite>

And the next one in app.component.ts:

favButtonChanged(eventArgs: { newValue: boolean }) {
    console.log("Favorite changed", + eventArgs);
  }

The idea is that everytime the button changes (toggles color and html), this event to log in the console "Favorite changed" + 0/1 (a boolean value). It logs: Favorite changed NaN.

Where is the problem?

Balastrong · Accepted Answer · 2021-10-19 18:17:06Z

1

You wrote console.log("Favorite changed", + eventArgs);

There's a comma , so you're passing two parameters to console.log and the second parameter is + eventArgs which tries to convert eventArgs into a number.

As you declared, eventArgs is clearly not a number (NaN means Not a Number) so the conversion (from the + sign) fails.

You might want to remove that +.

answered Oct 19, 2021 at 18:17

Balastrong

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Comments

abhishek sahu · Accepted Answer · 2021-10-19 18:34:55Z

0

here eventArgs is an object which will get NaN due to + you need write eventArgs.newValue which is boolean value & get converted into 1/0 Please try the below code

console.log("Favorite changed ", +eventArgs.newValue)

edited Oct 19, 2021 at 18:34

answered Oct 19, 2021 at 18:19

abhishek sahu

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