CODEWITHSUNDEEP
javascriptinheritance
J Seabolt
J Seabolt

Reputation: 2998

Prototypal Inheritance confusion

I expected this to result in 'woof,' but I'm getting undefined. Clearly not doing something correctly. Can someone tell me what I'm doing wrong here? 

const barker = (state) => {
  return {
    speak: () => console.log(state.sound)
  }
}

const newAnimal = sound => {
  let state = {
    sound
  }
  console.log(state.sound)
  return Object.assign({}, barker(state))
}

console.log(newAnimal("woof").speak())

Upvotes: -1

Views: 45

Answers (2)

Dai
Dai

Reputation: 155708

Here's your problem:

speak: () => console.log( state.sound )

barker returns an Object with a function-property speak which does not return a value (aka undefined). It has the type () => void because console.log does not return a value.

You can change it to this:

speak: () => {
    console.log( state.sound );
    return state.sound;
}

Or even just this (without logging):

speak: () => state.sound;

Upvotes: 1

Stefan Octavian
Stefan Octavian

Reputation: 620

Your code works perfectly. It outputs 'woof' 2 times (once from console.log inside newAnimal and once inside speak()). You get undefined because you also output the result of the speak method which is the return value of console.log, which is always undefined.

Upvotes: 1

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