UNPKG

is-number/README.md

Version:

2.1 kBMarkdownView Raw

1# is-number [![NPM version](https://badge.fury.io/js/is-number.svg)](http://badge.fury.io/js/is-number)
2
3> Returns true if the value is a number. comprehensive tests.
4
5To understand some of the rationale behind the decisions made in this library (and to learn about some oddities of number evaluation in JavaScript), [see this gist][gist].
6
7
8## Install
9## Install with [npm](npmjs.org)
10
11```bash
12npm i is-number --save
13```
14
15
16## Usage
17
18```js
19var isNumber = require('is-number');
20```
21
22### true
23
24```js
25isNumber(5e3);
26
27isNumber(0xff);
28
29isNumber(-1.1);
30isNumber(0);
31isNumber(1);
32isNumber(1.1);
33isNumber(10);
34isNumber(10.10);
35isNumber(100);
36
37isNumber('-1.1');
38isNumber('0');
39isNumber('012');
40isNumber('0xff');
41isNumber('1');
42isNumber('1.1');
43isNumber('10');
44isNumber('10.10');
45isNumber('100');
46isNumber('5e3');
47
48isNumber(parseInt('012'));
49isNumber(parseFloat('012'));
50
51isNumber(Infinity);
52isNumber('Infinity');
53```
54
55### Infinity
56
57Infinity can be [treated as a number][infinity] in mathematics. Here, it's a number - primarily because 99% of use cases do not require checking for it, but doing so [makes our function 20-35% slower](./benchmark/code/infinity.js) in common use cases.
58
59If you want `Infinity` to be `false`, just do:
60
61```js
62var isNumber = require('is-number');
63
64function isNum(val) {
65  return isNumber(val) && isFinite(val);
66}
67```
68
69### false
70
71```js
72isNumber('3abc');
73isNumber('abc');
74isNumber('abc3');
75isNumber('null');
76isNumber('undefined');
77isNumber([1, 2, 3]);
78isNumber(function () {});
79isNumber(new Buffer('abc'));
80isNumber(null);
81isNumber(undefined);
82isNumber({abc: 'abc'});
83isNumber({});
84isNumber([]);
85```
86
87
88## Run tests
89
90```bash
91npm test
92```
93
94## Author
95
96**Jon Schlinkert**
97 
98+ [github/jonschlinkert](https://github.com/jonschlinkert)
99+ [twitter/jonschlinkert](http://twitter.com/jonschlinkert) 
100
101## License
102Copyright (c) 2015 Jon Schlinkert  
103Released under the MIT license
104
105***
106
107_This file was generated by [verb](https://github.com/assemble/verb) on January 24, 2015._
108
109[infinity]: http://en.wikipedia.org/wiki/Infinity
110[gist]: https://gist.github.com/jonschlinkert/e30c70c713da325d0e81
\No newline at end of file

1	`# is-number [![NPM version](https://badge.fury.io/js/is-number.svg)](http://badge.fury.io/js/is-number)`
2
3	`> Returns true if the value is a number. comprehensive tests.`
4
5	`To understand some of the rationale behind the decisions made in this library (and to learn about some oddities of number evaluation in JavaScript), [see this gist][gist].`
6
7
8	`## Install`
9	`## Install with [npm](npmjs.org)`
10
11	```bash
12	`npm i is-number --save`
13	```
14
15
16	`## Usage`
17
18	```js
19	`var isNumber = require('is-number');`
20	```
21
22	`### true`
23
24	```js
25	`isNumber(5e3);`
26
27	`isNumber(0xff);`
28
29	`isNumber(-1.1);`
30	`isNumber(0);`
31	`isNumber(1);`
32	`isNumber(1.1);`
33	`isNumber(10);`
34	`isNumber(10.10);`
35	`isNumber(100);`
36
37	`isNumber('-1.1');`
38	`isNumber('0');`
39	`isNumber('012');`
40	`isNumber('0xff');`
41	`isNumber('1');`
42	`isNumber('1.1');`
43	`isNumber('10');`
44	`isNumber('10.10');`
45	`isNumber('100');`
46	`isNumber('5e3');`
47
48	`isNumber(parseInt('012'));`
49	`isNumber(parseFloat('012'));`
50
51	`isNumber(Infinity);`
52	`isNumber('Infinity');`
53	```
54
55	`### Infinity`
56
57	`Infinity can be [treated as a number][infinity] in mathematics. Here, it's a number - primarily because 99% of use cases do not require checking for it, but doing so [makes our function 20-35% slower](./benchmark/code/infinity.js) in common use cases.`
58
59	If you want `Infinity` to be `false`, just do:
60
61	```js
62	`var isNumber = require('is-number');`
63
64	`function isNum(val) {`
65	`return isNumber(val) && isFinite(val);`
66	`}`
67	```
68
69	`### false`
70
71	```js
72	`isNumber('3abc');`
73	`isNumber('abc');`
74	`isNumber('abc3');`
75	`isNumber('null');`
76	`isNumber('undefined');`
77	`isNumber([1, 2, 3]);`
78	`isNumber(function () {});`
79	`isNumber(new Buffer('abc'));`
80	`isNumber(null);`
81	`isNumber(undefined);`
82	`isNumber({abc: 'abc'});`
83	`isNumber({});`
84	`isNumber([]);`
85	```
86
87
88	`## Run tests`
89
90	```bash
91	`npm test`
92	```
93
94	`## Author`
95
96	`Jon Schlinkert`
97
98	`+ [github/jonschlinkert](https://github.com/jonschlinkert)`
99	`+ [twitter/jonschlinkert](http://twitter.com/jonschlinkert)`
100
101	`## License`
102	`Copyright (c) 2015 Jon Schlinkert`
103	`Released under the MIT license`
104
105	`***`
106
107	`_This file was generated by [verb](https://github.com/assemble/verb) on January 24, 2015._`
108
109	`[infinity]: http://en.wikipedia.org/wiki/Infinity`
110	`[gist]: https://gist.github.com/jonschlinkert/e30c70c713da325d0e81`
\	No newline at end of file