# Something totally new I learnt in JavaScript from Chat GPT

Today I learnt something totally brand new in JavaScript from ChatGPT !

```javascript
let foo = () =>
{
	return { monthly: 3, onetime: 6 };
}

let obj = { x:0, monthly: 0, onetime: 0, y:0 };
```

How do I do the following?

```javascript
{ obj.monthly, obj.onetime } = foo();
```

To assign the values returned by the foo() function to the **obj.monthly** and **obj.onetime** properties, you can use object destructuring. Here's the updated code:

```javascript
let foo = () => {
  return { monthly: 3, onetime: 6 };
};

let obj = { x: 0, monthly: 0, onetime: 0, y: 0 };

({ monthly: obj.monthly, onetime: obj.onetime } = foo());
```

In this code, object destructuring is used to extract the `monthly` and `onetime` properties from the object returned by the `foo()` function. The destructured properties are then assigned to the corresponding properties of the `obj` object using the syntax `property: target`.

After executing this code, `obj.monthly` will have the value `3` and `obj.onetime` will have the value `6`, matching the values returned by the `foo()` function.

My Q : Why is there a parenthesis surrounding `{ monthly: obj.monthly, onetime: obj.onetime } = foo()` ?

The parentheses surrounding `{ monthly: obj.monthly, onetime: obj.onetime }` in `({ monthly: obj.monthly, onetime: obj.onetime } = foo())` are necessary for syntactic reasons.

In JavaScript, when you have a statement that starts with a curly brace `{`, it is interpreted as a block statement rather than an object literal. Wrapping the entire assignment statement in parentheses helps clarify that you are performing an object destructuring assignment.

Without the parentheses, the JavaScript interpreter would treat `{ monthly: obj.monthly, onetime: obj.onetime }` as a block statement rather than an object literal, resulting in a syntax error.

Therefore, the parentheses are used to explicitly indicate that the intention is to destructure the returned object from `foo()` and assign its properties to `obj.monthly` and `obj.onetime`.