SlimIO IS

Node.js JavaScript Type checker (Primitives, Objects, etc..)

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

Why

• Focus on type checking (no fancy feature).
• Focus on Node.js support.
• Come with a TypeScript definition (which works).
• Is concerned about being stable.

Requirements

• Node.js v16 or higher.

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 { strictEqual } = require("assert");
const is = require("@slimio/is");

strictEqual(is.bool(true), true);
strictEqual(is.string("hello"), true);
strictEqual(is.map(new Map()), true);
strictEqual(is.func(() => {}), true);

The is const namespace is a Plain JavaScript Object with a lot of exported methods (check the below API Documentation).

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.object({}) | | 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("") | | emptyString | is.emptyString("") |

Dependencies

This project have no dependencies.

License

MIT