Type hints in V8

[matt0st...@gmail.com]

I read an article from 2012 that says V8 tags variables as types internally: https://www.html5rocks.com/en/tutorials/speed/v8/#toc-topic-numbers

Should I add hints for the optimizer to type in the constructor of a class if it's going to be used as either a float, integer, boolean or array respectively later on? By later on I mean used in an initializer function or something.

class Foo {

    constructor() {

        this.x = 0.0; // double

        this.y = 0; // int

        this.z = true; // boolean

        this.w = []; // array

    }

}

[Mathias Bynens]

See https://v8.dev/blog/react-cliff:

• Always initialize your objects in the same way, so that shapes can be effective.
• Choose sensible initial values for your fields to help JavaScript engines with representation selection.

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[matt0st...@gmail.com]

So in the end, it doesn't really matter that much as the React bug mentioned in the article was fixed? And there are no "elegant" ways of defining a double (e.g. let x = 0.0;) unless you use something like 0.000001, Number.MIN_VALUE, -0, or Infinity?

tirsdag 2. juni 2020 12.58.22 UTC+2 skrev Mathias Bynens følgende:

See https://v8.dev/blog/react-cliff:

• Always initialize your objects in the same way, so that shapes can be effective.
• Choose sensible initial values for your fields to help JavaScript engines with representation selection.

On Tue, Jun 2, 2020 at 12:43 PM <matt0st...@gmail.com> wrote:

I read an article from 2012 that says V8 tags variables as types internally: https://www.html5rocks.com/en/tutorials/speed/v8/#toc-topic-numbers

Should I add hints for the optimizer to type in the constructor of a class if it's going to be used as either a float, integer, boolean or array respectively later on? By later on I mean used in an initializer function or something.

class Foo {

    constructor() {

        this.x = 0.0; // double

        this.y = 0; // int

        this.z = true; // boolean

        this.w = []; // array

    }

}

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