CODEWITHSUNDEEP
javascriptprototypejavascript-objects
Ben Aston
Ben Aston

Reputation: 55729

Why is Object.prototype instanceof Object false?

Why does the following return false?

Object.prototype instanceof Object

Upvotes: 8

Views: 715

Answers (2)

Bergi
Bergi

Reputation: 664548

Because it basically asks whether Object.prototype does inherit from Object's .prototype object: It does not.

a instanceof b is equivalent to b.prototype.isPrototypeOf(a) - it tests whether b.prototype is in the prototype chain of a. In your case, it is not in the chain, because it is the start of the chain itself. isPrototypeOf is not reflexive.

Upvotes: 11

Etheryte
Etheryte

Reputation: 25310

Referencing MDN:

The instanceof operator tests whether an object has in its prototype chain the prototype property of a constructor.

Upvotes: 0

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