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  • License MIT

robust type checking for js

Package Exports

  • utils-type

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (utils-type) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

utils-type NPM version

documentation - install - notes - todo

build

simple

var type = require('utils-type');

type(42);              // -> { number: 42 }
type(NaN);             // -> { nan: true }
type(null);            // -> { null: true }
type(true);            // -> { boolean: true }
type(false);           // -> { boolean: true }
type(Infinity);        // -> { infinity: Infinity }
type(undefined);       // -> { undefined: true }
type('a string');       // -> { string: 'a string' }
type(/a regex/);       // -> { object: /a regex/, regexp: /a regex/ } }
type(function(){ });   // -> { object: [Function], function: [Function] }
type({ type : 'toy' });  // -> { object: { type: 'toy' } }
type(new Date());      // -> { object: Mon Sep 08 2014 19:10:32,  date: Mon Sep 08 2014 19:10:32 GMT+0200 (CEST) }
type(new Error());     // -> { object: [Error], error: [Error] }
type(new Stream());
// -> {
//   object: { domain: null, _events: {}, _maxListeners: 10 },
//   stream: { domain: null, _events: {}, _maxListeners: 10 },
//   eventemitter: { domain: null, _events: {}, _maxListeners: 10 }
// }

composition

The function returns an object. The type matched by that type returns itself.

type(1).number                      // -> 1 (that is truthy)
type([1,2,3]).array                 // -> [1,2,3] (truthy)
type(type([1,2,3]).array[1]).number // -> 1 (truthy)

comprehensive

type(-1).number            // -> -1
type(-1).integer           // -> -1
type(NaN).nan              // -> true
type(0.4).float            // -> 0.4
type(Infinity).infinity    // -> Infinity
type(new EventEmitter())
// -> {
//   object: { domain: null, _events: {}, _maxListeners: 10 },
//   eventemitter: { domain: null, _events: {}, _maxListeners: 10 }
// }

falsy values maintain the value if it makes sense

type(0).number             // -> true
type(0).integer            // -> 0
type('').string            // -> ' '
type(null).null            // -> true
type(NaN).number           // -> undefined
type(false).boolean        // -> true
type(undefined).undefined  // -> true

Why:

  • NaN is not a number
  • false is a boolean, returning it will be misleading
  • 0 is a number, but for integer its value its maintained
  • the empty string is changed to an space so is truthy and operations can be made on it
  • null and undefined are self explanatory

--- ### Documentation

The module.exports a function

var type = require('utils-type');

that takes one argument.

type

function type(value)

arguments

  • value type any, from where types will be obtained

returns

  • object with as many properties as types the argument has
var type = require('utils-type');
var items = type([1,2,3]);
Object.keys(items); // =>
// ['object', 'array']

install

With npm

$ npm install utils-type

test

$ npm test

notes

The module uses Objec.create in order to not produce false positives when checking properties on the returned object. So it basically needs support for object create. Polyfill it, for more info:

http://kangax.github.io/compat-table/es5/

todo

  • Include browser tests

license

LICENSE