Package Exports

@slimio/is

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Readme

SlimIO IS

NodeJS JavaScript Type checker (Primitives, Objects, etc..)

Package heavily inspired by @sindresorhus/is. This package aims to work on NodeJS (no browser support).

MIT

Getting Started

This package is available in the Node Package Repository and can be easily installed with npm or yarn.

$ npm i @slimio/is
# or
$ yarn add @slimio/is

Usage example

const is = require("@slimio/is");

console.log(is.string("hello")); // true;
console.log(is.map(new Map())); // true

The is variable is an Object with a lot of methods (check the below API section).

API

All methods can be called as follow: is.{methodName}. All methods return a boolean value.

Primitives

method	example
string	`is.string("hello")`
number	`is.number(10)`
boolean	`is.boolean(true)`
bool	`is.bool(false)`
symbol	`is.symbol(Symbol("foo"))`
undefined	`is.undefined(undefined)`
bigint	`is.bigint(50n)`
nullValue	`is.nullValue(null)`
nullOrUndefined	`is.nullOrUndefined(null
primitive	`is.primitive("hello")`

is.null is not available because of a name restriction.

Objects

method	example
promise	`is.promise(new Promise())`
classObject	`is.classObject(new Class{})`
array	`is.array([])`
object	`is.nullValue({})`
plainObject	`is.plainObject(Object.create(null))`
set	`is.set(new Set())`
map	`is.map(new Map())`
weakMap	`is.weakMap(new WeakMap())`
weakSet	`is.weakSet(new WeakSet())`
error	`is.error(new Error("ooppss!"))`
date	`is.date(new Date())`
regExp	`is.regExp(/^hello world$/)`
buffer	`is.buffer(Buffer.from("hello"))`

is.class is not available because of a name restriction.

Functions & Iterators

method	example
func	`is.func(new Function())`
generatorFunction	N/A
asyncFunction	`is.asyncFunction(async function() {})`
boundFunction	`is.boundFunction((function(){}).bind(null))`
iterable	`is.iterable([1, 2])`
asyncIterable	N/A
generator	N/A

is.function has been reduced to is.func because of a name restriction.

Typed Arrays

method	example
typedArray	`is.typedArray(new int8Array())`
int8Array	`is.int8Array(new int8Array())`
uint8Array	`is.uint8Array(new uint8Array())`
uint8ClampedArray	`is.uint8ClampedArray(new uint8ClampedArray())`
int16Array	`is.int16Array(new int16Array())`
uint16Array	`is.uint16Array(new uint16Array())`
int32Array	`is.int32Array(new int32Array())`
uint32Array	`is.uint32Array(new uint32Array())`
float32Array	`is.float32Array(new float32Array())`
float64Array	`is.float64Array(new float64Array())`
arrayBuffer	`is.arrayBuffer(new ArrayBuffer())`
sharedArrayBuffer	`is.sharedArrayBuffer(new SharedArrayBuffer())`
dataView	`is.dataView(new DataView(new ArrayBuffer(8)))`

Misc

method	example
nan	`is.nan(Number("booom!"))`
integer	`is.integer(5 / 10)`
directInstanceOf	`is.directInstanceOf(Object, {})`
truthy	`is.truthy(true)`
falsy	`is.falsy("")`

Why

Only focus on javascript type checking (without any other fancy feature).
Come with a well writed TypeScript definition.
Documented and tested (100% Coverage).
Focus on NodeJS support.
Maintained by the SlimIO team.
Is concerned about being stable.

Licence

MIT