Exploring Constructors and Factories in Javascript - Constructor InstanceOf Guard Example

index.js

var Person = require('./person')

console.log(name) // undefined
console.log(age) // undefined

var sean = Person('Sean Hagstrom', 20)

console.log(sean.name) // Sean Hagstrom
console.log(sean.age) // 20

console.log(name) // undefined
console.log(age) // undefined

person.js

function Person(name, age) {
  if(!(this instanceof Person)) {
    return new Person(name, age)
  }

  this.name = name
  this.age = age
}

module.exports = Person