utilise/is.js

Lean JavaScript Utilities as Micro-libraries

module.exports = is
is.fn      = isFunction
is.str     = isString
is.num     = isNumber
is.obj     = isObject
is.lit     = isLiteral
is.bol     = isBoolean
is.truthy  = isTruthy
is.falsy   = isFalsy
is.arr     = isArray
is.null    = isNull
is.def     = isDef
is.in      = isIn
is.promise = isPromise
is.stream  = isStream

function is(v){
  return function(d){
    return d == v
  }
}

function isFunction(d) {
  return typeof d == 'function'
}

function isBoolean(d) {
  return typeof d == 'boolean'
}

function isString(d) {
  return typeof d == 'string'
}

function isNumber(d) {
  return typeof d == 'number'
}

function isObject(d) {
  return typeof d == 'object'
}

function isLiteral(d) {
  return d.constructor == Object
}

function isTruthy(d) {
  return !!d == true
}

function isFalsy(d) {
  return !!d == false
}

function isArray(d) {
  return d instanceof Array
}

function isNull(d) {
  return d === null
}

function isDef(d) {
  return typeof d !== 'undefined'
}

function isPromise(d) {
  return d instanceof Promise
}

function isStream(d) {
  return !!(d && d.next)
}

function isIn(set) {
  return function(d){
    return !set ? false  
         : set.indexOf ? ~set.indexOf(d)
         : d in set
  }
}