Node.js module

util/types

The 'node:util/types' submodule provides type-checking utility functions for Node.js internal and user objects. It includes checks like isRegExp, isDate, isBuffer, and many others.

Use these functions to identify built-in object types accurately in userland code.

Functions 42

types.isAnyArrayBuffer()
Returns true if the value is a built-in ArrayBuffer or SharedArrayBuffer instance.
types.isArgumentsObject()
Returns true if the value is an arguments object.
types.isArrayBuffer()
Returns true if the value is a built-in ArrayBuffer instance.
types.isArrayBufferView()
Returns true if the value is an instance of one of the ArrayBuffer views, such as typed array objects or DataView.
types.isAsyncFunction()
Returns true if the value is an async function.
types.isBigInt64Array()
Returns true if the value is a BigInt64Array instance.
types.isBigIntObject()
Returns true if the value is a BigInt object, e.g.
types.isBigUint64Array()
Returns true if the value is a BigUint64Array instance.
types.isBooleanObject()
Returns true if the value is a boolean object, e.g.
types.isBoxedPrimitive()
Returns true if the value is any boxed primitive object, e.g.
types.isCryptoKey()
Returns true if value is a CryptoKey, false otherwise.
types.isDataView()
Returns true if the value is a built-in DataView instance.
types.isDate()
Returns true if the value is a built-in Date instance.
types.isExternal()
Returns true if the value is a native External value.
types.isFloat16Array()
Returns true if the value is a built-in Float16Array instance.
types.isFloat32Array()
Returns true if the value is a built-in Float32Array instance.
types.isFloat64Array()
Returns true if the value is a built-in Float64Array instance.
types.isGeneratorFunction()
Returns true if the value is a generator function.
types.isGeneratorObject()
Returns true if the value is a generator object as returned from a built-in generator function.
types.isInt16Array()
Returns true if the value is a built-in Int16Array instance.
types.isInt32Array()
Returns true if the value is a built-in Int32Array instance.
types.isInt8Array()
Returns true if the value is a built-in Int8Array instance.
types.isKeyObject()
Returns true if value is a KeyObject, false otherwise.
types.isMap()
Returns true if the value is a built-in Map instance.
types.isMapIterator()
Returns true if the value is an iterator returned for a built-in Map instance.
types.isModuleNamespaceObject()
Returns true if the value is an instance of a Module Namespace Object.
types.isNumberObject()
Returns true if the value is a number object, e.g.
types.isPromise()
Returns true if the value is a built-in Promise.
types.isProxy()
Returns true if the value is a Proxy instance.
types.isRegExp()
Returns true if the value is a regular expression object.
types.isSet()
Returns true if the value is a built-in Set instance.
types.isSetIterator()
Returns true if the value is an iterator returned for a built-in Set instance.
types.isSharedArrayBuffer()
Returns true if the value is a built-in SharedArrayBuffer instance.
types.isStringObject()
Returns true if the value is a string object, e.g.
types.isSymbolObject()
Returns true if the value is a symbol object, created by calling Object() on a Symbol primitive.
types.isTypedArray()
Returns true if the value is a built-in TypedArray instance.
types.isUint16Array()
Returns true if the value is a built-in Uint16Array instance.
types.isUint32Array()
Returns true if the value is a built-in Uint32Array instance.
types.isUint8Array()
Returns true if the value is a built-in Uint8Array instance.
types.isUint8ClampedArray()
Returns true if the value is a built-in Uint8ClampedArray instance.
types.isWeakMap()
Returns true if the value is a built-in WeakMap instance.
types.isWeakSet()
Returns true if the value is a built-in WeakSet instance.