call, bind & constructors. "this" is strange

call-bind-construct-this.js

function learning_context(arg) {
  console.log(arg)
  console.log(this.prop)
}

let bound_context = {
  prop: "bound"
}

let call_context = {
  prop: "call"
}

// learning_context("flying solo")
learning_context.call(call_context, "called arg")
let bound_learning = learning_context.bind(bound_context);
bound_learning("bound arg")

// let's make "this" work 
new learning_context("constructored arg")

// https://goo.gl/WPSBJ6