type-detect

Improved typeof detection for node.js and the browser.

Installation

Node.js

type-detect is available on npm.

$ npm install type-detect

Component

type-detect is available as a component.

$ component install chaijs/type-detect

Usage

Primary

The primary export of type-detect is function that can server as a replacement for typeof. The results of this function will be more specific than that of native typeof.

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

array

assert(type([]) === 'array');
assert(type(new Array()) === 'array');

regexp

assert(type(/a-z/gi) === 'regexp');
assert(type(new RegExp('a-z')) === 'regexp');

function

assert(type(function () {}) === 'function');

arguments

(function () {
  assert(type(arguments) === 'arguments');
})();

date

assert(type(new Date) === 'date');

number

assert(type(1) === 'number');
assert(type(1.234) === 'number');
assert(type(-1) === 'number');
assert(type(-1.234) === 'number');
assert(type(Infinity) === 'number');
assert(type(NaN) === 'number');
assert(type(new Number(1)) === 'number');

string

assert(type('hello world') === 'string');
assert(type(new String('hello')) === 'string');

null

assert(type(null) === 'null');
assert(type(undefined) !== 'null');

undefined

assert(type(undefined) === 'undefined');
assert(type(null) !== 'undefined');

object

var Noop = function () {};
assert(type({}) === 'object');
assert(type(Noop) !== 'object');
assert(type(new Noop) === 'object');
assert(type(new Object) === 'object');

ECMA6 Types

Supports all ECMA6 Types:

assert(type(new Map() === 'map');
assert(type(new WeakMap()) === 'weakmap');
assert(type(new Set()) === 'set');
assert(type(new WeakSet()) === 'weakset');
assert(type(Symbol()) === 'symbol');
assert(type(new Promise(callback) === 'promise');
assert(type(new Int8Array()) === 'int8array');
assert(type(new Uint8Array()) === 'uint8array');
assert(type(new UInt8ClampedArray()) === 'uint8clampedarray');
assert(type(new Int16Array()) === 'int16array');
assert(type(new Uint16Array()) === 'uint16array');
assert(type(new Int32Array()) === 'int32array');
assert(type(new UInt32Array()) === 'uint32array');
assert(type(new Float32Array()) === 'float32array');
assert(type(new Float64Array()) === 'float64array');
assert(type(new ArrayBuffer()) === 'arraybuffer');
assert(type(new DataView(arrayBuffer)) === 'dataview');

If you use Symbol.toStringTag to change an Objects return value of the toString() Method, type() will return this value, e.g:

var myObject = {};
myObject[Symbol.toStringTag] = 'myCustomType';
assert(type(myObject) === 'myCustomType');

Library

A Library is a small constructed repository for custom type detections.

var lib = new type.Library;

.of (obj)

@param {Mixed} object to test
@return {String} type

Expose replacement typeof detection to the library.

if (lib.of('hello world') === 'string') {
  // ...
}

.define (type, test)

@param {String} type
@param {RegExp|Function} test

Add a test to for the .test() assertion.

Can be defined as a regular expression:

lib.define('int', /^[0-9]+$/);

… or as a function:

lib.define('bln', function (obj) {
  if (lib.of(obj) === 'boolean') return true;
  var blns = [ 'yes', 'no', 'true', 'false', 1, 0 ];
  if (lib.of(obj) === 'string') obj = obj.toLowerCase();
  return !! ~blns.indexOf(obj);
});

.test (obj, test)

@param {Mixed} object
@param {String} type
@return {Boolean} result

Assert that an object is of type. Will first check natives, and if that does not pass it will use the user defined custom tests.

assert(lib.test('1', 'int'));
assert(lib.test('yes', 'bln'));

License

(The MIT License)

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.