Guard Helpers

Utility functions for working with guard operations.

Functions

Function	Description
isArray	Checks if a value is an array.
isArrayBuffer	Checks if a value is an ArrayBuffer instance.
isArrayLike	Checks if a value is array-like: has a non-negative integer `length` property.
isAsyncFunction	Checks if a value is an async function.
isAsyncGenerator	Checks if a value is an async generator object (the result of calling an `async function*`).
isAsyncGeneratorFunction	Checks if a value is an async generator function (an `async function*` declaration or expression).
isAsyncIterable	Checks if a value implements the async iterable protocol.
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.
isBrowser	Checks whether the code is currently running in a browser-like environment (`window` and `window.document` both defined…
isCssColor	Checks whether a value is a syntactically-safe, plain CSS color: a hex color (`#rgb`, `#rgba`, `#rrggbb`, `#rrggbbaa`),…
isDate	Checks if a value is a Date instance.
isDefined	Checks if a value is defined (not undefined nor null).
isError	Checks if a value is an Error instance.
isFalsy	Checks if a value is falsy (`false`, `null`, `undefined`, `0`, `“”`, `NaN`).
isFormData	Checks if a value is a FormData instance.
isFunction	Checks if a value is a function.
isGenerator	Checks if a value is a generator object (the result of calling a `function*`).
isGeneratorFunction	Checks if a value is a generator function (a `function*` declaration or expression).
isIterable	Checks if a value is iterable (has a `Symbol.iterator` method).
isJSON	Checks whether a value is a string containing valid, parseable JSON text.
isJSONArray	Checks whether a value is an array whose every element is a valid JSON value (see isJSONValue).
isJSONObject	Checks whether a value is a plain object whose every own value is a valid JSON value (see isJSONValue).
isJSONValue	Checks whether a value is composed entirely of JSON-representable types: `string`, finite `number`, `boolean`, `null`, …
isLength	Checks whether a value is a valid array-like `length`: a non-negative safe integer (`0 <= value <= Number.MAX_SAFE_INTE…
isMap	Checks if a value is a Map instance.
isNode	Checks whether the code is currently running in a Node.js-like environment (`process.versions.node` is defined — also t…
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.
isPrimitive	Checks if a value is a JavaScript primitive.
isPromise	Checks if a value is a Promise or a thenable.
isPromiseLike	Checks if a value is a thenable (has a `.then()` method).
isPropertyKey	Checks if a value is a valid property key: `string`, `number`, or `symbol`.
isRegExp	Checks if a value is a RegExp instance.
isSet	Checks if a value is a Set instance.
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`.
isValidRegex	Checks if a string is a valid regex pattern.
isWeakMap	Checks if a value is a WeakMap instance.
isWeakSet	Checks if a value is a WeakSet instance.