1 # kind-of [![NPM version](https://img.shields.io/npm/v/kind-of.svg?style=flat)](https://www.npmjs.com/package/kind-of) [![NPM monthly downloads](https://img.shields.io/npm/dm/kind-of.svg?style=flat)](https://npmjs.org/package/kind-of) [![NPM total downloads](https://img.shields.io/npm/dt/kind-of.svg?style=flat)](https://npmjs.org/package/kind-of) [![Linux Build Status](https://img.shields.io/travis/jonschlinkert/kind-of.svg?style=flat&label=Travis)](https://travis-ci.org/jonschlinkert/kind-of)
3 > Get the native type of a value.
7 Install with [npm](https://www.npmjs.com/):
10 $ npm install --save kind-of
13 Install with [bower](https://bower.io/)
16 $ bower install kind-of --save
21 > es5, browser and es6 ready
24 var kindOf = require('kind-of');
38 kindOf(new Boolean(true));
41 kindOf(new Buffer(''));
47 kindOf(new Number(42));
53 kindOf(new String('str'));
62 kindOf(Object.create(null));
83 kindOf(new RegExp('foo'));
86 kindOf(function () {});
89 kindOf(function * () {});
92 kindOf(new Function());
98 kindOf(new WeakMap());
104 kindOf(new WeakSet());
107 kindOf(Symbol('str'));
110 kindOf(new Int8Array());
113 kindOf(new Uint8Array());
116 kindOf(new Uint8ClampedArray());
117 //=> 'uint8clampedarray'
119 kindOf(new Int16Array());
122 kindOf(new Uint16Array());
125 kindOf(new Int32Array());
128 kindOf(new Uint32Array());
131 kindOf(new Float32Array());
134 kindOf(new Float64Array());
140 Benchmarked against [typeof](http://github.com/CodingFu/typeof) and [type-of](https://github.com/ForbesLindesay/type-of).
141 Note that performaces is slower for es6 features `Map`, `WeakMap`, `Set` and `WeakSet`.
145 current x 23,329,397 ops/sec ±0.82% (94 runs sampled)
146 lib-type-of x 4,170,273 ops/sec ±0.55% (94 runs sampled)
147 lib-typeof x 9,686,935 ops/sec ±0.59% (98 runs sampled)
150 current x 27,197,115 ops/sec ±0.85% (94 runs sampled)
151 lib-type-of x 3,145,791 ops/sec ±0.73% (97 runs sampled)
152 lib-typeof x 9,199,562 ops/sec ±0.44% (99 runs sampled)
155 current x 20,190,117 ops/sec ±0.86% (92 runs sampled)
156 lib-type-of x 5,166,970 ops/sec ±0.74% (94 runs sampled)
157 lib-typeof x 9,610,821 ops/sec ±0.50% (96 runs sampled)
160 current x 23,855,460 ops/sec ±0.60% (97 runs sampled)
161 lib-type-of x 5,667,740 ops/sec ±0.54% (100 runs sampled)
162 lib-typeof x 10,010,644 ops/sec ±0.44% (100 runs sampled)
165 current x 27,061,047 ops/sec ±0.97% (96 runs sampled)
166 lib-type-of x 13,965,573 ops/sec ±0.62% (97 runs sampled)
167 lib-typeof x 8,460,194 ops/sec ±0.61% (97 runs sampled)
170 current x 25,075,682 ops/sec ±0.53% (99 runs sampled)
171 lib-type-of x 2,266,405 ops/sec ±0.41% (98 runs sampled)
172 lib-typeof x 9,821,481 ops/sec ±0.45% (99 runs sampled)
175 current x 3,348,980 ops/sec ±0.49% (99 runs sampled)
176 lib-type-of x 3,245,138 ops/sec ±0.60% (94 runs sampled)
177 lib-typeof x 9,262,952 ops/sec ±0.59% (99 runs sampled)
180 current x 21,284,827 ops/sec ±0.72% (96 runs sampled)
181 lib-type-of x 4,689,241 ops/sec ±0.43% (100 runs sampled)
182 lib-typeof x 8,957,593 ops/sec ±0.62% (98 runs sampled)
185 current x 25,379,234 ops/sec ±0.58% (96 runs sampled)
186 lib-type-of x 3,635,148 ops/sec ±0.76% (93 runs sampled)
187 lib-typeof x 9,494,134 ops/sec ±0.49% (98 runs sampled)
190 current x 27,459,221 ops/sec ±1.01% (93 runs sampled)
191 lib-type-of x 14,360,433 ops/sec ±0.52% (99 runs sampled)
192 lib-typeof x 23,202,868 ops/sec ±0.59% (94 runs sampled)
206 In 7 out of 8 cases, this library is 2x-10x faster than other top libraries included in the benchmarks. There are a few things that lead to this performance advantage, none of them hard and fast rules, but all of them simple and repeatable in almost any code library:
208 1. Optimize around the fastest and most common use cases first. Of course, this will change from project-to-project, but I took some time to understand how and why `typeof` checks were being used in my own libraries and other libraries I use a lot.
209 2. Optimize around bottlenecks - In other words, the order in which conditionals are implemented is significant, because each check is only as fast as the failing checks that came before it. Here, the biggest bottleneck by far is checking for plain objects (an object that was created by the `Object` constructor). I opted to make this check happen by process of elimination rather than brute force up front (e.g. by using something like `val.constructor.name`), so that every other type check would not be penalized it.
210 3. Don't do uneccessary processing - why do `.slice(8, -1).toLowerCase();` just to get the word `regex`? It's much faster to do `if (type === '[object RegExp]') return 'regex'`
216 * [is-glob](https://www.npmjs.com/package/is-glob): Returns `true` if the given string looks like a glob pattern or an extglob pattern… [more](https://github.com/jonschlinkert/is-glob) | [homepage](https://github.com/jonschlinkert/is-glob "Returns `true` if the given string looks like a glob pattern or an extglob pattern. This makes it easy to create code that only uses external modules like node-glob when necessary, resulting in much faster code execution and initialization time, and a bet")
217 * [is-number](https://www.npmjs.com/package/is-number): Returns true if the value is a number. comprehensive tests. | [homepage](https://github.com/jonschlinkert/is-number "Returns true if the value is a number. comprehensive tests.")
218 * [is-primitive](https://www.npmjs.com/package/is-primitive): Returns `true` if the value is a primitive. | [homepage](https://github.com/jonschlinkert/is-primitive "Returns `true` if the value is a primitive. ")
222 Pull requests and stars are always welcome. For bugs and feature requests, [please create an issue](../../issues/new).
226 | **Commits** | **Contributor** |
228 | 64 | [jonschlinkert](https://github.com/jonschlinkert) |
229 | 2 | [miguelmota](https://github.com/miguelmota) |
230 | 1 | [dtothefp](https://github.com/dtothefp) |
231 | 1 | [ksheedlo](https://github.com/ksheedlo) |
232 | 1 | [pdehaan](https://github.com/pdehaan) |
233 | 1 | [laggingreflex](https://github.com/laggingreflex) |
237 _(This project's readme.md is generated by [verb](https://github.com/verbose/verb-generate-readme), please don't edit the readme directly. Any changes to the readme must be made in the [.verb.md](.verb.md) readme template.)_
239 To generate the readme, run the following command:
242 $ npm install -g verbose/verb#dev verb-generate-readme && verb
247 Running and reviewing unit tests is a great way to get familiarized with a library and its API. You can install dependencies and run tests with the following command:
250 $ npm install && npm test
257 * [github/jonschlinkert](https://github.com/jonschlinkert)
258 * [twitter/jonschlinkert](https://twitter.com/jonschlinkert)
262 Copyright © 2017, [Jon Schlinkert](https://github.com/jonschlinkert).
263 Released under the [MIT License](LICENSE).
267 _This file was generated by [verb-generate-readme](https://github.com/verbose/verb-generate-readme), v0.6.0, on May 19, 2017._