Why is ES6 “yield” a reserved word when called in this context?

Question

I am using node 4.1.1. When I run this code

\"use strict\";

function *generator() {
  let numbers = [1,2,3,4,5];
  numbers.map(n => yield (n + 1));
}

f         


        

Answer 1

That's because the arrow function is not a generator. If I expand your arrow function, it would look something like:

function *generator() {      // <-- this is your generator function
  let numbers = [1,2,3,4,5];
  numbers.map(function(n){   // <-- this one isn't a generator
    yield (n + 1)            // <-- there's your yield
  }.bind(this));
}