to-regex-range

Pass two numbers, get a regex-compatible source string for matching ranges. Validated against more than 2.78 million test assertions.

Please consider following this project's author, Jon Schlinkert, and consider starring the project to show your ❤️ and support.

Install

Install with npm:

$ npm install --save to-regex-range

const toRegexRange = require('to-regex-range');
const regex = new RegExp(toRegexRange('15', '95'));

Usage

Add this library to your javascript application with the following line of code

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

The main export is a function that takes two integers: the min value and max value (formatted as strings or numbers).

const source = toRegexRange('15', '95');
//=> 1[5-9]|[2-8][0-9]|9[0-5]

const regex = new RegExp(`^${source}$`);
console.log(regex.test('14')); //=> false
console.log(regex.test('50')); //=> true
console.log(regex.test('94')); //=> true
console.log(regex.test('96')); //=> false

Options

options.capture

Type: boolean

Deafault: undefined

Wrap the returned value in parentheses when there is more than one regex condition. Useful when you're dynamically generating ranges.

console.log(toRegexRange('-10', '10'));
//=> -[1-9]|-?10|[0-9]

console.log(toRegexRange('-10', '10', { capture: true }));
//=> (-[1-9]|-?10|[0-9])

options.shorthand

Type: boolean

Deafault: undefined

Use the regex shorthand for [0-9]:

console.log(toRegexRange('0', '999999'));
//=> [0-9]|[1-9][0-9]{1,5}

console.log(toRegexRange('0', '999999', { shorthand: true }));
//=> \d|[1-9]\d{1,5}

options.relaxZeros

Type: boolean

Default: true

This option relaxes matching for leading zeros when when ranges are zero-padded.

const source = toRegexRange('-0010', '0010');
const regex = new RegExp(`^${source}$`);
console.log(regex.test('-10')); //=> true
console.log(regex.test('-010')); //=> true
console.log(regex.test('-0010')); //=> true
console.log(regex.test('10')); //=> true
console.log(regex.test('010')); //=> true
console.log(regex.test('0010')); //=> true

When relaxZeros is false, matching is strict:

const source = toRegexRange('-0010', '0010', { relaxZeros: false });
const regex = new RegExp(`^${source}$`);
console.log(regex.test('-10')); //=> false
console.log(regex.test('-010')); //=> false
console.log(regex.test('-0010')); //=> true
console.log(regex.test('10')); //=> false
console.log(regex.test('010')); //=> false
console.log(regex.test('0010')); //=> true

Examples

Heads up!

Order of arguments

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

toRegexRange('51', '29');

Is effectively flipped to:

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

Steps / increments

This library does not support steps (increments). A pr to add support would be welcome.

History

v2.0.0 - 2017-04-21

New features

Adds support for zero-padding!

v1.0.0

Optimizations

Repeating ranges are now grouped using quantifiers. rocessing time is roughly the same, but the generated regex is much smaller, which should result in faster matching.

Attribution

Inspired by the python library range-regex.

About

$ npm install && npm test

$ npm install -g verbose/verb#dev verb-generate-readme && verb

Related projects

You might also be interested in these projects:

• expand-range: Fast, bash-like range expansion. Expand a range of numbers or letters, uppercase or lowercase. Used… more | homepage
• fill-range: Fill in a range of numbers or letters, optionally passing an increment or step to… more | homepage
• 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

Contributors

Author

Jon Schlinkert

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License

Copyright © 2019, Jon Schlinkert. Released under the MIT License.

This file was generated by verb-generate-readme, v0.8.0, on April 07, 2019.