1 # fill-range [![NPM version](https://img.shields.io/npm/v/fill-range.svg?style=flat)](https://www.npmjs.com/package/fill-range) [![NPM monthly downloads](https://img.shields.io/npm/dm/fill-range.svg?style=flat)](https://npmjs.org/package/fill-range) [![NPM total downloads](https://img.shields.io/npm/dt/fill-range.svg?style=flat)](https://npmjs.org/package/fill-range) [![Linux Build Status](https://img.shields.io/travis/jonschlinkert/fill-range.svg?style=flat&label=Travis)](https://travis-ci.org/jonschlinkert/fill-range)
3 > Fill in a range of numbers or letters, optionally passing an increment or `step` to use, or create a regex-compatible range with `options.toRegex`
9 - [Examples](#examples)
11 * [options.step](#optionsstep)
12 * [options.strictRanges](#optionsstrictranges)
13 * [options.stringify](#optionsstringify)
14 * [options.toRegex](#optionstoregex)
15 * [options.transform](#optionstransform)
18 _(TOC generated by [verb](https://github.com/verbose/verb) using [markdown-toc](https://github.com/jonschlinkert/markdown-toc))_
22 Install with [npm](https://www.npmjs.com/):
25 $ npm install --save fill-range
28 Install with [yarn](https://yarnpkg.com):
36 Expands numbers and letters, optionally using a `step` as the last argument. _(Numbers may be defined as JavaScript numbers or strings)_.
39 var fill = require('fill-range');
40 fill(from, to[, step, options]);
43 console.log(fill('1', '10')); //=> '[ '1', '2', '3', '4', '5', '6', '7', '8', '9', '10' ]'
44 console.log(fill('1', '10', {toRegex: true})); //=> [1-9]|10
49 * `from`: **{String|Number}** the number or letter to start with
50 * `to`: **{String|Number}** the number or letter to end with
51 * `step`: **{String|Number|Object|Function}** Optionally pass a [step](#optionsstep) to use.
52 * `options`: **{Object|Function}**: See all available [options](#options)
56 By default, an array of values is returned.
58 **Alphabetical ranges**
61 console.log(fill('a', 'e')); //=> ['a', 'b', 'c', 'd', 'e']
62 console.log(fill('A', 'E')); //=> [ 'A', 'B', 'C', 'D', 'E' ]
67 Numbers can be defined as actual numbers or strings.
70 console.log(fill(1, 5)); //=> [ 1, 2, 3, 4, 5 ]
71 console.log(fill('1', '5')); //=> [ 1, 2, 3, 4, 5 ]
76 Numbers can be defined as actual numbers or strings.
79 console.log(fill('-5', '-1')); //=> [ '-5', '-4', '-3', '-2', '-1' ]
80 console.log(fill('-5', '5')); //=> [ '-5', '-4', '-3', '-2', '-1', '0', '1', '2', '3', '4', '5' ]
83 **Steps (increments)**
86 // numerical ranges with increments
87 console.log(fill('0', '25', 4)); //=> [ '0', '4', '8', '12', '16', '20', '24' ]
88 console.log(fill('0', '25', 5)); //=> [ '0', '5', '10', '15', '20', '25' ]
89 console.log(fill('0', '25', 6)); //=> [ '0', '6', '12', '18', '24' ]
91 // alphabetical ranges with increments
92 console.log(fill('a', 'z', 4)); //=> [ 'a', 'e', 'i', 'm', 'q', 'u', 'y' ]
93 console.log(fill('a', 'z', 5)); //=> [ 'a', 'f', 'k', 'p', 'u', 'z' ]
94 console.log(fill('a', 'z', 6)); //=> [ 'a', 'g', 'm', 's', 'y' ]
101 **Type**: `number` (formatted as a string or number)
103 **Default**: `undefined`
105 **Description**: The increment to use for the range. Can be used with letters or numbers.
111 console.log(fill('1', '10', 2)); //=> [ '1', '3', '5', '7', '9' ]
112 console.log(fill('1', '10', 3)); //=> [ '1', '4', '7', '10' ]
113 console.log(fill('1', '10', 4)); //=> [ '1', '5', '9' ]
116 console.log(fill('a', 'z', 5)); //=> [ 'a', 'f', 'k', 'p', 'u', 'z' ]
117 console.log(fill('a', 'z', 7)); //=> [ 'a', 'h', 'o', 'v' ]
118 console.log(fill('a', 'z', 9)); //=> [ 'a', 'j', 's' ]
121 ### options.strictRanges
127 **Description**: By default, `null` is returned when an invalid range is passed. Enable this option to throw a `RangeError` on invalid ranges.
131 The following are all invalid:
134 fill('1.1', '2'); // decimals not supported in ranges
135 fill('a', '2'); // incompatible range values
136 fill(1, 10, 'foo'); // invalid "step" argument
139 ### options.stringify
143 **Default**: `undefined`
145 **Description**: Cast all returned values to strings. By default, integers are returned as numbers.
150 console.log(fill(1, 5)); //=> [ 1, 2, 3, 4, 5 ]
151 console.log(fill(1, 5, {stringify: true})); //=> [ '1', '2', '3', '4', '5' ]
158 **Default**: `undefined`
160 **Description**: Create a regex-compatible source string, instead of expanding values to an array.
165 // alphabetical range
166 console.log(fill('a', 'e', {toRegex: true})); //=> '[a-e]'
167 // alphabetical with step
168 console.log(fill('a', 'z', 3, {toRegex: true})); //=> 'a|d|g|j|m|p|s|v|y'
170 console.log(fill('1', '100', {toRegex: true})); //=> '[1-9]|[1-9][0-9]|100'
171 // numerical range with zero padding
172 console.log(fill('000001', '100000', {toRegex: true}));
173 //=> '0{5}[1-9]|0{4}[1-9][0-9]|0{3}[1-9][0-9]{2}|0{2}[1-9][0-9]{3}|0[1-9][0-9]{4}|100000'
176 ### options.transform
180 **Default**: `undefined`
182 **Description**: Customize each value in the returned array (or [string](#optionstoRegex)). _(you can also pass this function as the last argument to `fill()`)_.
187 // increase padding by two
188 var arr = fill('01', '05', function(val, a, b, step, idx, arr, options) {
189 return repeat('0', (options.maxLength + 2) - val.length) + val;
193 //=> ['0001', '0002', '0003', '0004', '0005']
200 * [braces](https://www.npmjs.com/package/braces): Fast, comprehensive, bash-like brace expansion implemented in JavaScript. Complete support for the Bash 4.3 braces… [more](https://github.com/jonschlinkert/braces) | [homepage](https://github.com/jonschlinkert/braces "Fast, comprehensive, bash-like brace expansion implemented in JavaScript. Complete support for the Bash 4.3 braces specification, without sacrificing speed.")
201 * [expand-range](https://www.npmjs.com/package/expand-range): Fast, bash-like range expansion. Expand a range of numbers or letters, uppercase or lowercase. See… [more](https://github.com/jonschlinkert/expand-range) | [homepage](https://github.com/jonschlinkert/expand-range "Fast, bash-like range expansion. Expand a range of numbers or letters, uppercase or lowercase. See the benchmarks. Used by micromatch.")
202 * [micromatch](https://www.npmjs.com/package/micromatch): Glob matching for javascript/node.js. A drop-in replacement and faster alternative to minimatch and multimatch. | [homepage](https://github.com/jonschlinkert/micromatch "Glob matching for javascript/node.js. A drop-in replacement and faster alternative to minimatch and multimatch.")
203 * [to-regex-range](https://www.npmjs.com/package/to-regex-range): Pass two numbers, get a regex-compatible source string for matching ranges. Validated against more than… [more](https://github.com/jonschlinkert/to-regex-range) | [homepage](https://github.com/jonschlinkert/to-regex-range "Pass two numbers, get a regex-compatible source string for matching ranges. Validated against more than 2.87 million test assertions.")
207 Pull requests and stars are always welcome. For bugs and feature requests, [please create an issue](../../issues/new).
211 | **Commits** | **Contributor** |
213 | 103 | [jonschlinkert](https://github.com/jonschlinkert) |
214 | 2 | [paulmillr](https://github.com/paulmillr) |
215 | 1 | [edorivai](https://github.com/edorivai) |
216 | 1 | [wtgtybhertgeghgtwtg](https://github.com/wtgtybhertgeghgtwtg) |
220 _(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.)_
222 To generate the readme, run the following command:
225 $ npm install -g verbose/verb#dev verb-generate-readme && verb
230 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:
233 $ npm install && npm test
240 * [github/jonschlinkert](https://github.com/jonschlinkert)
241 * [twitter/jonschlinkert](https://twitter.com/jonschlinkert)
245 Copyright © 2017, [Jon Schlinkert](https://github.com/jonschlinkert).
246 Released under the [MIT License](LICENSE).
250 _This file was generated by [verb-generate-readme](https://github.com/verbose/verb-generate-readme), v0.5.0, on April 23, 2017._