Class extends Uint8Array, how to return Uint8Array?

Question

I have this custom simple class:

class U8a extends Uint8Array {
  logMe() {
    return this.subarray(0);
  }
}

And I ran this code:

const u = new U8a([1, 2, 3]);
console.log(u.logMe());

Expected result:

Uint8Array [ 1, 2, 3 ]

Actual result:

U8a [Uint8Array] [ 1, 2, 3 ]

Is it possible to return the result as an Uint8Array only?

Are you sure this is a typescript, not merely javascript question? — Nurbol Alpysbayev
– Nurbol Alpysbayev, Commented Oct 23, 2018 at 14:46
What is the problem u instanceof Uint8Array => true you just extend so the u is Uint8Array object — Muhammed Albarmavi
– Muhammed Albarmavi, Commented Oct 23, 2018 at 14:47
@malbarmawi Now I can do u.logMe().logMe(). I want to disable this. — jeanpaul62
– jeanpaul62, Commented Oct 23, 2018 at 14:50
Why would you expect Uint8Array? That's not what it is: "The subarray() method returns a new TypedArray on the same ArrayBuffer store and with the same element types as for this TypedArray object." Plus it'd make your logging explicitly incorrect. You could use #from and create a new array. — Dave Newton
– Dave Newton, Commented Oct 23, 2018 at 14:52
@DaveNewton Yes, that's what I expected too. Hence this question, the title translates to: is it possible to actually return an Uint8Array on the same ArrayBuffer store? — jeanpaul62
– jeanpaul62, Commented Oct 23, 2018 at 14:55

Muhammed Albarmavi · Accepted Answer · 2018-10-23 15:01:10Z

1

Update logMe method to return new instant of Uint8Array so will not have the logMe method.

class U8a extends Uint8Array {
  logMe() {
    return new Uint8Array(this.entries());
  }
}

const u = new U8a([1, 2, 3]);
const u2 = u.logMe();
console.log(u2.logMe()); throw Uncaught TypeError: u2.logMe is not a function

answered Oct 23, 2018 at 15:01

Muhammed Albarmavi

24.5k9 gold badges72 silver badges92 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Class extends Uint8Array, how to return Uint8Array?

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related