javascript - Destructure object and reassign to different variable name in one go - Stack Overflow

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I have an object:

let obj = {
  "t":
    {
      "en": {
        "head" :"hello",
        "sub"  : "this is great"
      }
    }
  "link": {}
}

and I'm destructuring it:

{ t: { en }}

is it possible to reassign t to en in the same destructuring statement?

So I want the object assigned to en in the variable t not in en

I have an object:

let obj = {
  "t":
    {
      "en": {
        "head" :"hello",
        "sub"  : "this is great"
      }
    }
  "link": {}
}

and I'm destructuring it:

{ t: { en }}

is it possible to reassign t to en in the same destructuring statement?

So I want the object assigned to en in the variable t not in en

• javascript
• ecmascript-6
• syntax

Share Improve this question Follow edited Oct 12, 2018 at 8:57 supersize asked Oct 11, 2018 at 19:12 supersizesupersize 14.8k1919 gold badges8585 silver badges144144 bronze badges 0

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3 Answers 3

Sorted by: Reset to default 8

When you're destructuring an object, you can specify propname: variablename to assign the property to a variable with a different name. Putting just the property name without a variable is equivalent to propname: propname, to use the same name for the variable and property, but you don't need to use that shortcut.

So you can do it like this:

let obj = {
  "t":
    {
      "en": {
        "head" :"hello",
        "sub"  : "this is great"
      }
    }
}

let { t: { en: t } } = obj;
console.log(t);

The first t: is just a property name, it specifies that the value is an object which needs to be destructured as well. In that structure, we use the propname: variablename syntax, so the en property is assigned to the t variable.

In a function definition this would look like:

const Home = ({ t: { en: t }, link}) => console.log(t);

let obj = {
  "t":
    {
      "en": {
        "head" :"hello",
        "sub"  : "this is great"
      }
    }
};
Home(obj);

Note that there's no actual relationship between the two uses of t. The variable can actually be anything, e.g.

const Home = ({ t: { en: blah }, link}) => console.log(blah);

No, it's impossible to reassign t, because t is a const. If t weren't a const, then yes, it would be possible to reassign it:

let t = {
  "en":
    {
      "head": "hello",
      "sub" : "this is great"
    }
};

({ en: t } = t);
console.log(t);

Note that

{ t: <something>

would only be done with destructuring if t were a property of the parent object - but here, t is a standalone variable, not a property so instead, start with

{ en: <something>

with t on the right-hand side.

If t actually is a property of the parent object, then you can do the same sort of thing:

let obj = {
  "t":
    {
      "en": {
        "head" :"hello",
        "sub"  : "this is great"
      }
    },
  "link": {}
};
const { t: { en: t } } = obj;
console.log(t);

You could do this in one line in the following manner:

let obj = {
  "t":
    {
      "en": {
        "head" :"hello",
        "sub"  : "this is great"
      }
    }
}

// here we are destructuring en but declaring 
// it as a variable which is called t
let { en: t } =  obj.t;

console.log(t)

We can choose an alias in a destructuring assignment using a colon.

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