typeOf

A utility for retrieving the type of a JS value.

Install

npm i @ibnlanre/typeof

Import

// ES6 Import
import typeOf from "@ibnlanre/typeof"

// NodeJS Require
const typeOf = require("@ibnlanre/typeof");

Usage

typeOf([1, "two", 3]) // array
typeOf(JSON, { quirksMode: true }) // object
typeOf(async() => {}) // function
typeOf(new Set([0])[Symbol.iterator]()) // setiterator

Browser

You can also use typeOf within the browser, but only as a module.

<script src="http://unpkg.com/@ibnlanre/typeof" type="module">
  // CDN Service
</script>

<script src="./node_modules/@ibnlanre/typeof" type="module">
  // PKG manager
  console.log(typeOf(null)) // null
</script>

Reference

Some JavaScript Standard Built-ins compared with { quirkMode: true } results.

• Primitives

  typeOf(NaN) // number
  typeOf(-Infinity) // number
  typeOf(0) // number
  typeOf(new Number(1)) // number
  typeOf(2n) // bigint
  typeOf(BigInt(3)) // bigint
  typeOf("type") // string
  typeOf(new String("of")) // string
  typeOf(false) // boolean
  typeOf(new Boolean(true)) // boolean
  typeOf(new Object(1 > 2)) // boolean
  typeOf(Symbol("bar")) // symbol
  typeOf(undefined) // undefined
  typeOf(null) // null
  

• Functions

  typeOf(Object) // function
  typeOf(new Function()) // function
  typeOf((function () { return arguments })()) // arguments
  typeOf(() => { }) // function
  

• Control Abstractions

  typeOf(function*() {}) // generatorfunction
  typeOf((function*(x) { yield x })(0)) // generator
  typeOf(new Set([0, 9, 8])[Symbol.iterator]()) // setiterator
  typeOf(async() => { await 0 }) // asyncfunction
  

• Objects

  typeOf({ a: "apple", b: "ball" }) // object
  typeOf(new Object()) // object
  typeOf(new (class Library {})(), { quirksMode: true }) // library
  typeOf(new (class Library {})()) // object
  typeOf(/regEx/m) // regexp
  typeOf(new RegExp(/u/, "ig")) // regexp
  typeOf(new Date()) // date
  

• Global Properties

  typeOf(globalThis) // global
  typeOf(globalThis, { quirksMode: true }) // object
  
  // NodeJS
  typeOf(global, { quirksMode: true }) // object
  typeOf(global), // global
  

• Math

  typeOf(Math) // math
  typeOf(Math, { quirksMode: true }) // object
  

• JSON

  typeOf(JSON, { quirksMode: true }) // object
  typeOf(JSON) // json
  

• Error Objects

  typeOf(new Error()) // error
  typeOf(new SyntaxError()) // error
  typeOf(new SyntaxError(), { quirksMode: true }) // syntaxerror
  

• Array

  typeOf([1, "two"]) // array
  typeOf(new Array()) // array
  

• Structured Data

  typeOf(new ArrayBuffer()) // arraybuffer
  typeOf(new DataView(new ArrayBuffer())) // dataview
  

• Keyed Collections

  typeOf(new Map()) // map
  typeOf(new WeakMap()) // weakmap
  typeOf(new Set()) // set
  typeOf(new WeakSet()) // weakset
  

• Typed DataViews

  typeOf(new Int8Array()) //  int8array
  typeOf(new Uint8Array()) // uint8array
  typeOf(new Uint8ClampedArray()) // uint8clampedarray
  typeOf(new Int16Array()) // int16array
  typeOf(new Uint16Array()) // uint16array
  typeOf(new Int32Array()) // int32array
  typeOf(new Uint32Array()) // uint32array
  typeOf(new Float32Array()) // float32array
  typeOf(new Float64Array()) // float64array
  typeOf(new BigInt64Array()) // bigint64array
  typeOf(new BigUint64Array()) // biguint64array
  

• Buffer

  // NodeJS
  typeOf(Buffer.from("abc"), { quirksMode: true }) // buffer
  typeOf(Buffer.from("abc")) // uint8array
  

Custom Type

You may also use Symbol.toStringTag to change an object's return value

const testObject = {};
testObject[Symbol.toStringTag] = "customType";
typeOf(testObject, { quirksMode: true }) // object
typeOf(testObject) // customtype