Type/Since 1.38.0

isObject

Checks whether a value is a non-null JavaScript object.

isObject(value):value is object

Behavior

The function first excludes null, then checks whether typeof value is object. Because of this, arrays and built-in object instances such as Date, Map, and Set also return true.

Null Handling

Although typeof null returns object in JavaScript, the function explicitly excludes null by checking value !== null.

Type Guard

The return type is value is object, allowing TypeScript to narrow the value to object inside a conditional branch.

Parameters

valueunknownrequired

The value to check.

Returns

value is object

Returns true when the value is not null and its typeof result is object; otherwise, returns false.

Examples

Basic usage

Check whether different values are objects.

TypeScript

import { isObject } from "@cyref/js";

isObject({});
// true

isObject([]);
// true

isObject(new Date());
// true

isObject(null);
// false

isObject("hello");
// false

isObject(42);
// false

Type narrowing

isObject acts as a TypeScript type guard and narrows the value to object when it returns true.

TypeScript

const value: string | object = {};

if (isObject(value)) {
  // value is object
}

Built with@cyref/js·Official documentation