picky typeof

install

npm i picky_typoef

primitive value

import { typeOf } from 'pickey_typeof'

// number
typeOf(1).is('number') // true
typeOf(NaN).is('number') // true
typeOf(Infinity).is('number') // true
typeOf(1).isNaN() // false, why don't use native isNaN ?
typeOf(1).isInfinity() // false
typeOf(1).isNormalNumber() // true
typeOf(NaN).isNormalNumber() // false
typeOf(Infinity).isNormalNumber() // false

// string
typeOf('a').is('string') // true

// boolean
typeOf(true).is('boolean') // true

// symbol
typeOf(Symbol()).is('symbol') // true

// date
typeOf(new Date()).is('date') // true

reference value

compare with a.constructor.name

// object
typeOf({}).is('object') // true, only match [object Object]
 
// object-like
use constructor.name, worked with most of cases.
typeOf([]).is('array') // true
typeOf(new Map()).is('map') // true
typeOf(new Set()).is('set') // true
typeOf(new Buffer()).is('buffer') // true

// function
typeOf(() => {}).is('function') // true
typeOf(() => {}).is('AsyncFunction') // false
typeOf(async () => {}).is('AsyncFunction') // false

// class
class DemoClass () {}
typeOf(new DemoClass()).is('DemoClass') // true
typeOf(new DemoClass()).is(DemoClass) // true, a safer way

with Constructor

typeOf([]).is(Array) // true
typeOf(() => {}).is(Function) // true

Warning: When you pass in the constructor, instancesOf will actually be called for comparison. Object will return true in all cases. When it needs to be strictly judged as an ordinary object, use typeOf({}).is('object')

with ==

typeOf(() => {}) == 'function'// true
typeOf(NaN) == 'number'// true
typeOf(null) == 'null'// true
// Equality will call [Symbol.toPrimitive] to compare
// here don't use ===