typa

Typa

A super-simple JavaScript type checker. Mainly pilfered from this blog post by Webbjocke.

Install

  npm install typa

Import

  import {is} from 'typa'

  // or

  const is = require('typa')

Typa Function

Checks if value matches the specified type, then returns the first function or value if true or the second function or value if false.

Available Types

• str: String
• arr: Array
• obj: Object
• bool: Boolean
• date: Date
• empty: Empty string, array, or object
• err: Error
• fn: Function
• num: Number
• int: Integer
• json: JSON object
• nll: Null
• undef: Undefined
• noru: Null or undefined
• bad: Null, undefined, empty, or an error
• regex: Regular expression
• sym: Symbol

  $str = 'hello'
  $arr = 'hello'

  $fn1 = (() => console.log('hello'))
  $fn2 = (() => console.log('goodbye'))

  is.typa('str', $str, $fn1, $fn2)
    // => 'hello'

  is.typa('arr', $arr, $fn1, $fn2)
    // => 'goodbye'

Individual Checks

Array

  is.arr(['text', 12])
    // => true

Boolean

  is.bool(true)
    // => true

  is.bool(false)
    // => true

Date

  is.date(new Date())
    // => true

Empty

  is.empty('')
    // => true

  is.empty([])
    // => true

  is.empty({})
    // => true

Error

  is.err(new Error('This is an error.'))
    // => true

Function

  is.fn(() => { console.log('Hi!') })
    // => true

Integer

  is.int(12)
    // => true

JSON

  is.json('{"key": "value"}')
    // => true

Null

  is.nll(null)
    // => true

Null or Undefined

  is.noru(null)
    // => true

  is.noru(undefined)
    // => true

Number

  is.num(28.2)
    // => true

Object

  is.obj({ key: 'value' })
    // => true

Regex

  is.regex(new Regex(/\W/))
    // => true

String

  is.str('text')
    // => true

Symbol

  is.sym(Symbol(42))
    // => true

Undefined

  is.undef(undefined)
    // => true