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Solution Review: Check Instance of Variables

Solution Review: Check Instance of Variables

This lesson will explain the solution to the problem in the previous lesson.

We'll cover the following...

Solution #

Javascript (babel-node)
var tempFunc1 = function () {
    return {}
}
function check(){
    var object1 = new tempFunc1();
    var object2 = tempFunc1();
    return (object1 instanceof tempFunc1 === object2 instanceof tempFunc1);     
}
console.log(check())

Explanation #

This question is tricky as it tests your understanding of functions, constructor functions, and the instanceof operator.

Let’s start by understanding the original code first.

Javascript (babel-node)
var tempFunc1 = function () {
}
function check(){
    var object1 = new tempFunc1();
    var object2 = tempFunc1(); 
    return (object1 instanceof tempFunc1 === object2 instanceof tempFunc1);     
}
console.log(check())

The code has a function, tempFunc1, which has an empty body. The check function creates two variables, object1 and object, both storing different outputs from tempFunc1. How come?

On line 5, we call tempFunc1 as a constructor function by calling it with the ...