Can Constructors Return Values Other Than 'this'?

Return Values for Constructors That Bypass the "this" Reference

When invoking a constructor using the new keyword, the default behavior is for the constructor to return the newly created object (referred to as "this"). However, there are specific circumstances where a constructor can return a different value, effectively preventing the assignment of "this" to the newly created object.

According to the ECMAScript specification, step 8 of the [[Construct]] internal property defines the return behavior as follows:

If the type of the value returned by the constructor function (Result(6)) is not an Object:

- The value returned by the constructor will be returned instead of "`this`".

Therefore, to return a value other than "this" from a constructor:

1. Return a non-object primitive (such as a string, number, or boolean): If the returned value is a primitive, it will not be interpreted as an object, and thus the new object will not be returned.
2. Return a custom object or a non-null value with a type other than Object: This can be achieved using the Object.create() method or by assigning a different prototype to the created object.

Example:

function Foo() {
    return { name: "sample" };
}

var foo = new Foo();
console.log(foo instanceof Foo); // false

In this case, since the Foo constructor returns an object that is not an instance of the Foo constructor, (new Foo() instanceof Foo) will evaluate to false.

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