ducktyping.md

Duck Typing

It doesn't matter if it's a duck as long as it behaves (properties and methods match) like a duck.

class Duck {
  constructor(name) {
    this.name = name
  }
  takeOff() {
    console.log(`${this.name} is taking off`)
  }
  fly() {
    console.log(`${this.name} is flying`)
  }
}

Instances:

> const myDuck = new Duck('Larry')
> myDuck.name
'Larry'
> myDuck.takeOff()
Larry is taking off
> myDuck.fly()
Larry is flying

> const myPlane = new Duck('Roger')
> myPlane2.name
'Roger'
> myPlane2.takeOff()
Roger is taking off
undefined
> myPlane2.fly()
Roger is flying

Issues:

1. Inaccurate. Can lead to false positives.
2. The object's methods and properties have to be over arbitraty. How do you get agreement from other developers?