Jul 8, 2025 · The instanceof operator tests to see if the prototype property of a constructor appears anywhere in the prototype chain of an object. The return value is a boolean value. Its behavior can …

The instanceof operator returns true if an object is an instance of a specified object: instanceof is an ECMAScript3 (JavaScript 1999) feature. It is supported in all browsers: The spread (...) Operator.

Sep 26, 2025 · The instanceof operator allows to check whether an object belongs to a certain class. It also takes inheritance into account. Such a check may be necessary in many cases. For example, it …

Checks the current object and returns true if the object is of the specified object type. Here are some good examples and here is an example taken directly from Mozilla's developer site: One thing worth …

Jul 11, 2025 · The instanceof operator in JavaScript is used to check the type of an object at run time. It returns a boolean value if true then it indicates that the object is an instance of a particular class and …

In this tutorial, you'll learn how to use the JavaScript instanceof operator to determine if a constructor's prototype appears in the prototype chain of an object.

Understand how JavaScript’s instanceof operator works, when to use it, and why it matters for safe object type checking across complex applications.

Apr 16, 2025 · Learn how to use the instanceof keyword in JavaScript for checking object types, with examples and explanations.

Apr 28, 2025 · Get a clear breakdown of how JavaScript’s typeof and instanceof work behind the scenes, and why their results don’t always match what you’d expect.

Learn how to effectively utilize the instanceof operator in JavaScript for type checking with examples and best practices.