Why doesn't JavaScript ES6 support multi-constructor classes?

Question

I want to write my Javascript class like below.

class Option {
    constructor() {
        this.autoLoad = false;
    }

    constructor(key, value) {
               


        

Answer 1

Another option would be to allow your constructor to take an object that is bound to your class properties:

class Option {
  // Assign default values in the constructor object 
  constructor({key = 'foo', value, autoLoad = true} = {}) {
      this.key = key;
      // Or on the property with default (not recommended)
      this.value = value || 'bar';
      this.autoLoad = autoLoad;
      
      console.log('Result:', this);
  }
}

var option1 = new Option();
// Logs: {key: "foo", value: "bar", autoLoad: true}

var option2 = new Option({value: 'hello'});
// Logs: {key: "foo", value: "hello", autoLoad: true}

This is even more useful with Typescript as you can ensure type safety with the values passed in (i.e. key could only be a string, autoLoad a boolean etc).