construct obect property using deconstruct on other object

Question

Can I build object on the fly using deconsturct? Like I token is under this.request.body.token, how can I get the value and assign it to a object property? Tried below example it won't work:

const params = {
    token
} = this.request.body

console.log(params.token) //undefined

I have to do this

const reqBody = this.request.body

const params = {
  token: reqBody.token
}

console.log(params.token) //123

Possible duplicate of [ES2015 deconstructing into an object](https://stackoverflow.com/questions/35157549/es2015-deconstructing-into-an-object) — str, May 08 '18 at 07:09

score 0 · Accepted Answer · answered May 08 '18 at 07:09

0

Use a colon while destructuring to assign to a standalone variable with a different name than the property name:

const obj = { request: { body: { token: 'abc' } } };
// obj is equivalent to the `this` in your code

const { request: { body: reqBody } } = obj;
console.log(reqBody);

If you're OK with the variable name being just body, then it's even easier:

const obj = { request: { body: { token: 'abc' } } };
// obj is equivalent to the `this` in your code

const { request: { body } } = obj;
console.log(body);

answered May 08 '18 at 07:09

CertainPerformance

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I think I'll just stick to my old way this is so unreadable, btw thanks for the answer! – May 08 '18 at 07:26
Learning the new concise syntax is a *good* thing - don't be afraid of using it, it has its place. – CertainPerformance May 08 '18 at 07:29
1

Neither are arrow functions, the first time you come across them, nor are `for` loops, nor are many other syntax constructs, but don't let that stop you from learning them - they're useful, and once you know them, you'll use them whenever appropriate, and be happier as a result. – CertainPerformance May 08 '18 at 07:39

score 0 · Answer 2 · answered May 08 '18 at 07:10

0

If the object you are destructuring has a few standard properties, you can do this by omission using object rest:

const thisRequestBody = {
  a: 'a', 
  b: 'b',
  token: 'token'
}

const { a, b, ...params } = thisRequestBody;

console.log(params);

answered May 08 '18 at 07:10

Ori Drori

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this.request.body is the params send by the frontend, don't think should spread it – May 08 '18 at 07:27
It's rest and not spread, and it creates an object from all the properties you haven't explicitly destructured. – Ori Drori May 08 '18 at 07:28
why not just `const { ...params } = thisRequestBody`? – May 08 '18 at 07:34
Because then `params` would include the properties you don't need (`a` and `b` in the example). – Ori Drori May 08 '18 at 07:41

construct obect property using deconstruct on other object

2 Answers2