fill-range

What is fill-range?

The fill-range npm package is used to generate an array of numbers or strings based on a given range with support for steps, negative ranges, and pattern expansion. It is often used for creating lists of numbers, expanding number and letter sequences, and generating arrays based on patterns.

What are fill-range's main functionalities?

Number Range Generation

Generates an array of numbers from 1 to 5.

[...fillRange(1, 5)]

Letter Range Generation

Generates an array of letters from 'a' to 'e'.

[...fillRange('a', 'e')]

Pattern Expansion

Expands a pattern '1..3' and applies a transformation function to each value, resulting in ['item1', 'item2', 'item3'].

[...fillRange('1..3', { transform: (val) => `item${val}` })]

Step Support

Generates an array of numbers from 1 to 10 with a step of 2, resulting in [1, 3, 5, 7, 9].

[...fillRange(1, 10, { step: 2 })]

Negative Range Support

Generates an array of numbers from -3 to 3.

[...fillRange(-3, 3)]

Other packages similar to fill-range

range-generator

This package provides similar functionality to fill-range by generating an array of numbers within a specified range. It allows for custom steps and can handle both ascending and descending ranges. Compared to fill-range, it focuses specifically on number ranges and does not support pattern expansion or letter ranges.

lodash.range

Part of the Lodash utility library, lodash.range generates an array of numbers progressing from start up to, but not including, end. It supports steps and is a lightweight alternative for number range generation. However, it does not offer the pattern expansion or letter range capabilities that fill-range does.

README

fill-range

Fill in a range of numbers or letters, optionally passing an increment or multiplier to use.

Install with npm

npm i fill-range --save

Usage

var range = require('fill-range');

Params

range(start, stop, increment);

• start: the number or letter to start with
• end: the number or letter to end with
• step: optionally pass the increment to use. works for letters or numbers

Examples

range(1, 3)
//=> ['1', '2', '3']

range('1', '3')
//=> ['1', '2', '3']

range('0', '-5')
//=> [ '0', '-1', '-2', '-3', '-4', '-5' ]

range(-9, 9, 3)
//=> [ '-9', '-6', '-3', '0', '3', '6', '9' ])

range('-1', '-10', '-2')
//=> [ '-1', '-3', '-5', '-7', '-9' ]

range('1', '10', '2')
//=> [ '1', '3', '5', '7', '9' ]

range('a', 'e')
//=> ['a', 'b', 'c', 'd', 'e']

range('a', 'e', 2)
//=> ['a', 'c', 'e']

range('A', 'E', 2)
//=> ['A', 'C', 'E']

Custom function

Optionally pass a custom function as the third or fourth argument:

range('a', 'e', function (val, isNumber, pad, i) {
  if (!isNumber) {
    return String.fromCharCode(val) + i;
  }
  return val;
});
//=> ['a0', 'b1', 'c2', 'd3', 'e4']

Special characters

A special character may be passed as the third arg instead of a step increment. These characters can be pretty useful for brace expansion, creating file paths, test fixtures and similar use case.

range('a', 'z', SPECIAL_CHARACTER_HERE);

Supported characters

• +: repeat the given string n times
• |: create a regex-ready string, instead of an array
• >: collapse/join values to single array element
• ?: randomize the given pattern using randomatic

+

Repeat the first argument the number of times passed on the second argument.

Examples:

range('a', 3, '+');
//=> ['a', 'a', 'a']

range('abc', 2, '+');
//=> ['abc', 'abc']

|

Creates a regex-ready string from the expanded arguments.

Examples:

range('a', 'c', '|');
//=> ['(a|b|c)'

range('a', 'z', '|5');
//=> ['(a|f|k|p|u|z)'

>

Collapses all values in the returned array to a single value.

Examples:

range('a', 'e', '>');
//=> ['abcde']

range('5', '8', '>');
//=> ['5678']

range('2', '20', '2>');
//=> ['2468101214161820']

?

Uses randomatic to generate randomized alpha, numeric, or alpha-numeric patterns based on the provided arguments.

Examples:

(actual results would obviously be randomized)

Generate a 5-character, uppercase, alphabetical string:

range('A', 5, '?');
//=> ['NSHAK']

Generate a 5-digit random number:

range('0', 5, '?');
//=> ['36583']

Generate a 10-character alpha-numeric string:

range('A0', 10, '?');
//=> ['5YJD60VQNN']

See the randomatic repo for all available options and or to create issues or feature requests related to randomization.

Run tests

Install dev dependencies:

npm i -d && npm test

Related

• micromatch: wildcard/glob matcher for javascript. a faster alternative to minimatch.
• expand-range: uses fill-range for range expansion in strings
• braces: uses expand range to do range expansion in glob patterns and braces.

Contributing

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

Author

Jon Schlinkert

• github/jonschlinkert
• twitter/jonschlinkert

License

Copyright (c) 2014-2015 Jon Schlinkert
Released under the MIT license

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This file was generated by verb on January 25, 2015.