How to spread an object into a classes properties in JavaScript

user_2782583 0
Viewed 8785

Basically here's what I'm trying to accomplish.

class Person {
  constructor (obj) {
    this.first = ''
    this.last = ''
    this.age = ''

    if (obj) {
      Object.assign(this, ...obj)
    }
  }
}

const a = new Person()
console.log('Not spreading: ', a)

const b = new Person({ first: 'Alex', last: 'Cory', age: 27 })
console.log('Spreading: ', b)

Is there a way to spread an object like this to populate a class?

spread-syntax class javascript
4 Answers

I would personally prefer to use a seperate method as it is not possible to have multiple constructors in JS. In the following example I create new objects using a static fromObject() method which returns a new object. Therefore you can keep your normal constructor and create new objects using spread syntax as well.

Note: I am using typescript here.

export class Point {
    readonly x: number
    readonly y: number

    constructor(x: number, y: number) {
        this.x = x;
        this.y = y;
    }

    static fromObject({x, y}: {x: number, y: number}) {
        return new Point(x, y)
    }
}
user_129003610
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