How do you set object prop and return object in one line?

April 4, 2023

I’ve got this code:

const arr = [{name: 'fred', age: 20}, {name: 'john', age: 50}]

const result = arr.reduce((acc, item) => {
  acc[item.name] = item.age
  return acc
}, {})

console.log(result)

How do I make the following 2 lines into 1 line?

 acc[item.name] = item.age
 return acc

>Solution :

Use the spread syntax (...) to combine item with your new key/value, then use ({}) to directly return the object:

You could also use the destructing assignment to get name and age as separate variable in stead of item, see commented line for an example.

const arr = [{name: 'fred', age: 20}, {name: 'john', age: 50}]

const result = arr.reduce((acc, item) => ({ ...acc, [item.name]: item.age }), {})

// Or with a destructuring assignment
// arr.reduce((acc, { name, age }) => ({ ...acc, [name]: age }), {})

console.log(result)