prototypes.md

Prototypes

function Car(id){
  this.carId = id
  this.start = _ => `start ${this.carId}`
}

let car = new Car(5)
car.start()

If you were to instantiate a 1000 copies of Car, 100 copies of the function start would be created. This is inefficient and affects performance. Using prototypes, we ensure that only one copy start is created no matter how many objects of Car

function Car(id){
  this.carId = id
}

Car.prototype.start = function() {
  console.log('start ' + this.carId)
}

let car = new Car(5)
car.start()

Expand objects using prototypes

Expand object functionality by adding functions to object prototypes

String.prototype.hello = function(){
  return this.toString() + ' hello'
}

'foo'.hello()