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Object/Class/Interface destructuring #1473

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Object/Class/Interface destructuring#1473
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enhancement

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@jkelleyrtp
jkelleyrtp
opened on Sep 25, 2020

[enhancement]

Currently, it seems that destructuring is not supported. It is one of my most used TS features, and I'd like to see it in AssemblyScript.

There are many subtleties to destructuring, but the original TS repo has a well-documented history of changes:

microsoft/TypeScript#1346
microsoft/TypeScript#1463

We would ideally support

var [x, y] = [10, 20];
[x, y] = [y, x];

// and 

interface Foo { bar: f32, baz: f32 };
const { bar } = Foo;

// and

class Foo { bar: f32 = 10.0 };
const { bar } = new Foo();

Activity

  1. dcodeIO
    added
    enhancement
    on Sep 25, 2020

  2. MaxGraey commented on Sep 25, 2020

    @MaxGraey
    MaxGraey
    on Sep 25, 2020
    Member

    @dcodeIO I know in general case it required iterators, but most of time it will be optimized to simple stuffs. For example:

    const arr = [1, 2, 3, 4];
const [a, b] = arr;
const [first, second, ...tail] = arr;

    desugared to:

    var arr = [1, 2, 3, 4];
var a = arr[0], b = arr[1];
var first = arr[0], second = arr[1], tail = arr.slice(2);

    playground

    And I guess it already could be implemented with some limitations

  3. ExE-Boss commented on Mar 31, 2021

    @ExE-Boss
    ExE-Boss
    on Mar 31, 2021

    @MaxGraey That’s only if you don’t enable the downlevelIteration option.

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