This values for arrow functions [duplicate]

Answer 1

Let's transform into the equivalent ES5 code:

var test = {
  id: "123123",
  k: {
    laptop: "ramen",
    testfunc: function(){return console.log(this)}.bind(this)
  }
}

Remember that this depends on how you call the function. The outer this isn't inside a function, so it will default to undefined in strict mode.

Simplified scenario below:

console.log(this) // undefined

var test = {
  a: this // same `this` as above
}

Answer 2

You are defining the arrow function in the same scope that you defined var test. If you are defining test in the global scope, then the arrow function's context will be the global scope too.

If you are defining test inside of a method, the arrow function will share the method's context.

function method() {
  const self = this;

  const test = {
    foo: () => console.log(self === this);
  }

  test.foo()
  // console: true
}