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Question #15

Author: admin

tags: JavaScript

The following code is executed in the browser outside the module:

const Test = function() {
  this.num = 5;
  return { num: { valueOf: function() { return 2; } } };
};

const x = Test();

const y = new Test();

console.log(x.num + y.num); // ??

What will the console output be?

2

4

5

7

10

NaN

'2[object Object]'

'5[object Object]'

'[object Object]5'

'[object Object]2'

If the constructor function has a return, then when the constructor is called, even with the new operator, the usual behavior may change.

If an object is returned in return and not a primitive value, then this object is returned.

By the way, after executing the code from this task, the num property with the value 5 was created in the window object.

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