Preserve comments with object destructuring assignment

Tái hiện hành vi trong TypeScript Playground được liên kết, bằng cách so sánh các chú giải khi di chuột qua những thuộc tính được truy cập trực tiếp và các biến được tạo ra thông qua object destructuring. Theo dõi đường đi của language-service/type-checking để phân giải các chú thích cho các binding được phân rã; hoàn tất khi các chú thích của thuộc tính đã khai báo xuất hiện cho x, y và các tham số hàm được phân rã, mà không thay đổi đầu ra khi chạy.

Search Terms

object destructuring assignment, comment

Suggestion

interface MyInterface {
    /**
     * I am x
     */
    x : number;
    /**
     * I am y
     */
    y : number;
}
declare const myInterface : MyInterface;
const {x, y} = myInterface;

/**
 * Expected tooltip to have comment,
 * > I am x
 * 
 * Actual: No comment
 */
x;
/**
 * Expected tooltip to have comment,
 * > I am y
 * 
 * Actual: No comment
 */
y;

/**
 * Expected tooltip to have comment,
 * > I am x
 * 
 * Actual:
 * Tooltip has comment,
 * > I am x
 */
myInterface.x;

/**
 * Expected tooltip to have comment,
 * > I am y
 * 
 * Actual:
 * Tooltip has comment,
 * > I am y
 */
myInterface.y;

/**
 * I am z
 */
const z = 1;

/**
 * Expected tooltip to have comment,
 * > I am z
 * 
 * Actual:
 * Tooltip has comment,
 * > I am z
 */
z;

Playground

Use Cases

I came across this idea after writing code like this,

function foo (
  {
    somePropertyA,
    somePropertyB,
    somePropertyC,
  } : SomeObject
) {
  /* Use these properties */
}

And I was hazy on the details of what each property was for.
So, I hovered my cursor over the variables somePropertyA, somePropertyB, somePropertyC and noticed there were no comments.

I had to go to the declaration of somePropertyA, somePropertyB, somePropertyC and look at each property individually.

---

At the moment, the way to get comments is to just do,

function foo (
  o : SomeObject
) {
  /* Use these properties */
}

Then the tooltip for o.somePropertyA, o.somePropertyB, o.somePropertyC will have comments

Examples

See above suggestion

Checklist

My suggestion meets these guidelines:

• This wouldn't be a breaking change in existing TypeScript/JavaScript code
• This wouldn't change the runtime behavior of existing JavaScript code
• This could be implemented without emitting different JS based on the types of the expressions
• This isn't a runtime feature (e.g. library functionality, non-ECMAScript syntax with JavaScript output, etc.)
• This feature would agree with the rest of TypeScript's Design Goals.