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destructure-private

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Stage 2
Classification: Syntactic Change Semantic Change
Human Validated: KW
Title: Destructure Private Fields
Authors: Justin Ridgewell
Champions: Justin Ridgewell
Last Presented: December 2021
Stage Upgrades:
Stage 1: 2021-09-05
Stage 2: 2021-10-30
Stage 2.7: NA
Stage 3: NA
Stage 4: NA
Last Commit: 2024-07-15
Topics: objects
Keywords: private destructuring fields class
GitHub Link: https://github.com/tc39/proposal-destructuring-private
GitHub Note Link: https://github.com/tc39/notes/blob/HEAD/meetings/2021-12/dec-14.md#destructuring-private-fields

Proposal Description:

proposal-destructuring-private

A proposal to integrate private fields and destructuring.

class Foo {
  #x = 1;
 
  constructor() {
    console.log(this.#x); // => 1
    
    const { #x: x } = this;
    console.log(x); // => 1
  }
 
  equals({ #x: otherX }) {
    const { #x: currentX } = this;
    return currentX === otherX;
  }
}

Champions

Status

Current Stage: 2

Motivation

Destructuring is a popular feature to store local references to an object’s properties. Private Field’s proposal targeted the minimum features needed to support the goal of private properties in class instances. Unfortunately, this left destructuring out.

This proposal avoids questions of reification of Private Fields by limiting this to syntax only. It also doesn’t need to worry about “shorthand” syntax (#x in an expression being shorthand for this.#x), because the Committee has decided we will not persue shorthand syntax after the private-fields-in-in proposal.


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