Type Helpers

Utility functions for working with type operations.

Functions

Function	Description
isArray	Checks if a value is an array.
isArrayBuffer	Checks if a value is an ArrayBuffer instance.
isAsyncFunction	Checks if a value is an async function.
isBigInt	Checks if a value is a bigint.
isBlob	Checks if a value is a Blob instance.
isBoolean	Checks if a value is a boolean.
isBuffer	Checks if a value is a Node.js Buffer instance.
isDate	Checks if a value is a Date instance.
isDefined	Checks if a value is defined (not undefined nor null).
isDirectInstanceOf	native JS value.constructor === Foo (ES1)
isEmpty	Checks if a value is empty.
isError	Checks if a value is an Error instance.
isFalsy	Checks if a value is falsy (false, null, undefined, 0, "", NaN).
isFinite / isFiniteNumber	native JS Number.isFinite(value) (ES2015)
isFormData	Checks if a value is a FormData instance.
isFunction	Checks if a value is a function.
isHtmlElement / isUrlInstance / isUrlSearchParams	native JS value instanceof HTMLElement / URL / URLSearchParams (Web API)
isInteger	native JS Number.isInteger(value) (ES2015)
isIterable	Checks if a value is iterable (has a Symbol.iterator method).
isMap	Checks if a value is a Map instance.
isNaN	native JS Number.isNaN(value) (ES2015)
isNegativeNumber	Checks if a value is a number less than 0.
isNonEmptyArray	Checks if a value is a non-empty array (length > 0).
isNonEmptyString	Checks if a value is a non-empty string (length > 0).
isNull	Checks if a value is null.
isNullish	Checks if a value is null or undefined (nullish).
isNumber	Checks if a value is a number.
isPlainObject	Checks if a value is a plain object.
isPositiveNumber	Checks if a value is a number greater than 0.
isPrimitive	Checks if a value is a JavaScript primitive.
isPromise	Checks if a value is a Promise or a thenable.
isRegExp	Checks if a value is a RegExp instance.
isSafeInteger	native JS Number.isSafeInteger(value) (ES2015)
isSet (Set data structure)	native JS value instanceof Set (ES2015)
isSpecialObject	Determines if a value is a special object that should not have its properties compared deeply.
isString	Checks if a value is a string.
isSymbol	Checks if a value is a symbol.
isTemporalDuration	Checks if a value is a Temporal.Duration.
isTemporalInstant	Checks if a value is a Temporal.Instant.
isTemporalPlainDate	Checks if a value is a Temporal.PlainDate.
isTemporalPlainDateTime	Checks if a value is a Temporal.PlainDateTime.
isTemporalPlainTime	Checks if a value is a Temporal.PlainTime.
isTemporalZonedDateTime	Checks if a value is a Temporal.ZonedDateTime.
isTimestamp	Checks if a value is a valid timestamp (milliseconds or Unix seconds).
isTruthy	Checks if a value is truthy (not false, null, undefined, 0, "", or NaN).
isUndefined	Checks if a value is undefined.
isValidDate	Checks if a value is a valid Date instance (not Invalid Date).
isValidRegex	Checks if a string is a valid regex pattern.
isWeakMap / isWeakSet / isWeakRef	native JS value instanceof WeakMap / WeakSet / WeakRef (ES2015 / ES2021)
TypedArrays (isInt8Array, isFloat32Array, ...)	native JS value instanceof Int8Array / Float32Array / ... (ES2015)