Rediscovering JavaScript

Enhanced Object Literals

Creating an object by assigning fields with values from existing variables is a common operation. In the past this involved a lot of noisy code. Let’s consider the old way to create an object with a few fields and methods.

literals/without-enhanced-object-literals.js

const createPerson = function(name, age, sport, sportFn) {
  const person = {
    name: name,
    age: age,
    toString: function() {
      return this.name + ' '  + this.age;
    }
  };

  person['play' + sport] = sportFn;

  return person;
};

const sam =
  createPerson('Sam', 21, 'Soccer',
    function() { console.log(`${this.name}, kick, don't touch`); });

console.log(sam.name);
console.log(sam.toString());
sam.playSoccer(); ...