How to copy the properties of an inner object to the outer

Jul 20, 2021

Learn how to copy the properties of an inner object up to the outer object in JavaScript using Object.assign, so you avoid copying each property by hand.

~~~

Problem: I had a tweet object that for some reason related to the architecture of the app contained the actual tweet data into another object assigned to its data property.

Imagine this:

let tweet = {
  data: {
    id: 1,
    content: 'test'
  }
}

I wanted to move those inner properties on the top level object:

let tweet = {
  id: 1,
  content: 'test'
}

without manually copying those properties over, because the minute I add another property, I introduce a bug.

So here’s what I did:

tweet = Object.assign(tweet, tweet.data)

It’s the same technique you can use to copy properties to another object, but applied in a slightly different way.

Tagged: JavaScript · All topics

~~~