Object.prototype.isPrototypeOf()
Object.prototype.isPrototypeOf() is a JavaScript method in the Object category. Checks if an object exists in another's prototype chain. The syntax is obj.isPrototypeOf(target). A typical example: Array.prototype.isPrototypeOf([]) // true. A close sibling is Object.keys(), which returns an array of a given object's own enumerable property names. A close sibling is Object.values(), which returns an array of a given object's own enumerable property values. A close sibling is Object.entries(), which returns an array of key/value pairs. A close sibling is Object.assign(), which copies properties from source objects to a target. More about this category: Object methods for object manipulation — keys, values, assign, and more. Related Object methods: Object.keys(), Object.values(), Object.entries(), Object.assign(), Object.create(), Object.defineProperty(), Object.defineProperties(), Object.freeze(). This page is part of the free JS Reference documentation covering 1027+ methods, each with syntax, parameters, return values, examples, and common pitfalls.