to-regex-range

What is to-regex-range?

The to-regex-range npm package is designed to generate regular expressions for matching numeric ranges. It is useful for creating regex patterns that can match against specific ranges of numbers, allowing for precise control over numeric input validation, among other applications.

What are to-regex-range's main functionalities?

Generating regex for simple numeric ranges

This feature allows you to generate a regex pattern for a simple numeric range, such as from 5 to 10. The resulting regex will match any number within this range.

const toRegexRange = require('to-regex-range');
const regex = toRegexRange('5', '10');
console.log(regex); // => '5|6|7|8|9|10'

Creating regex with zero-padding

This feature enables the generation of regex patterns that account for zero-padded numbers, useful for matching numbers within a range where the number of digits is consistent.

const toRegexRange = require('to-regex-range');
const regex = toRegexRange('001', '100', { capture: true, pad: true });
console.log(regex); // Example output: '(0[0-9]{2}|1[0-9]{2})'

Generating regex for complex ranges with options

This feature allows for the creation of regex patterns for more complex numeric ranges with additional options, such as disabling the relaxation of leading zeros, providing more precise control over the matching behavior.

const toRegexRange = require('to-regex-range');
const regex = toRegexRange('10', '299', { relaxZeros: false });
console.log(regex); // Example output: '1[0-9]|2[0-9]{2}'

0

README

to-regex-range

Returns a regex-compatible range from two numbers, min and max. Validated against more than 1.1 million generated unit tests that run in less than 400ms! Useful for creating regular expressions to validate numbers, ranges, years, etc.

Install

Install with npm:

$ npm install --save to-regex-range

Notes

Validated against 1,117,543 generated unit tests, to provide brute-force verification that the generated regex-ranges are correct.

Usage

var toRegexRange = require('to-regex-range');

var re = new RegExp(toRegexRange('1', '99'));
re.test('50');
//=> true

Examples

console.log(toRegexRange('111', '555'));
//=> 11[1-9]|1[2-9][0-9]|[2-4][0-9]{2}|5[0-4][0-9]|55[0-5]

console.log(toRegexRange('5', '5'));
//=> 5

console.log(toRegexRange('5', '6'));
//=> [5-6]

console.log(toRegexRange('51', '229'));
//=> 5[1-9]|[6-9][0-9]|1[0-9]{2}|2[0-2][0-9]

console.log(toRegexRange('29', '51'));
//=> 29|[3-4][0-9]|5[0-1]

console.log(toRegexRange('1', '100000'));
//=> [1-9]|[1-9][0-9]{1,4}|100000

When the min is larger than the max, values will be flipped to create a valid range:

toRegexRange('51', '29');
//=> 29|[3-4][0-9]|5[0-1]

Heads up!

This library does not support steps (increments) or zero-padding.

History

v1.0

More optimizations! As of v1.0, repeating ranges are now grouped using quantifiers. Processing time is roughly the same, but the generated regex is much smaller, which should result in faster matching.

Key

(for the before/after comparison tables)

• range: the generated range, e.g. toRegexRange(1, 10000000)
• stats: size of the generated string, and processing time
• result: generated string

Before

Patterns generated before v1.0 changes:

Range | Stats | Result

--- | --- | --- 1..10000000 | 99 B (11ms 666μs) | ([1-9]|[1-9][0-9]|[1-9][0-9]{2}|[1-9][0-9]{3}|[1-9][0-9]{4}|[1-9][0-9]{5}|[1-9][0-9]{6}|10000000) 1..1000000 | 84 B (2ms 96μs) | ([1-9]|[1-9][0-9]|[1-9][0-9]{2}|[1-9][0-9]{3}|[1-9][0-9]{4}|[1-9][0-9]{5}|1000000) 1..100000 | 69 B (1ms 674μs) | ([1-9]|[1-9][0-9]|[1-9][0-9]{2}|[1-9][0-9]{3}|[1-9][0-9]{4}|100000) 1..10000 | 54 B (2ms 40μs) | ([1-9]|[1-9][0-9]|[1-9][0-9]{2}|[1-9][0-9]{3}|10000) 1..1000 | 39 B (1ms 263μs) | ([1-9]|[1-9][0-9]|[1-9][0-9]{2}|1000) 1..100 | 24 B (1ms 905μs) | ([1-9]|[1-9][0-9]|100) 1..10 | 12 B (383μs) | ([1-9]|10) 1..3 | 9 B (260μs) | ([1-3])

After

With v1.0 optimizations.

Range | Stats | Result

--- | --- | --- 1..10000000 | 34 B (11ms 702μs) | ([1-9]|[1-9][0-9]{1,6}|10000000) 1..1000000 | 33 B (1ms 274μs) | ([1-9]|[1-9][0-9]{1,5}|1000000) 1..100000 | 32 B (726μs) | ([1-9]|[1-9][0-9]{1,4}|100000) 1..10000 | 31 B (2ms 432μs) | ([1-9]|[1-9][0-9]{1,3}|10000) 1..1000 | 30 B (507μs) | ([1-9]|[1-9][0-9]{1,2}|1000) 1..100 | 24 B (267μs) | ([1-9]|[1-9][0-9]|100) 1..10 | 12 B (240μs) | ([1-9]|10) 1..3 | 9 B (665μs) | ([1-3])

Attribution

Inspired by the python lib range-regex.

About

Related projects

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• micromatch: Glob matching for javascript/node.js. A drop-in replacement and faster alternative to minimatch and multimatch. | homepage
• repeat-element: Create an array by repeating the given value n times. | homepage
• repeat-string: Repeat the given string n times. Fastest implementation for repeating a string. | homepage

Contributing

Pull requests and stars are always welcome. For bugs and feature requests, please create an issue.

Building docs

(This document was generated by verb-generate-readme (a verb generator), please don't edit the readme directly. Any changes to the readme must be made in .verb.md.)

To generate the readme and API documentation with verb:

$ npm install -g verb verb-generate-readme && verb

Running tests

Install dev dependencies:

$ npm install -d && npm test

Author

Jon Schlinkert

• github/jonschlinkert
• twitter/jonschlinkert

License

Copyright © 2016, Jon Schlinkert. Released under the MIT license.

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This file was generated by verb-generate-readme, v0.2.0, on October 19, 2016.