A collection of common string functions.
📦 Node.js, 🌐 Web, 📜 Files, 📰 Docs.

A string is a sequence of characters. In JavaScript, strings are not mutable. Any transfomation of a string, such as slice or concat generates a new string. The JavaScript runtime however may optimize this behavior by mutating strings behind the scenes, when it can be guarenteed that the previous string is not accessible to the programmer. The runtime may also avoid copying slices of a string, or even concatenation of slices of strings, by implementing it as a series of lookups into existing strings. Food for thought.

This package provides functions for generating spaces; querying about a string such as is, isEmpty, isCharacter, index, indexRange, codePointRange; comparing strings such as compare, isEqual; getting parts of a string such as get, getAll, set, begin, middle, end; searching a string such as longestCommonInfix, longestCommonPrefix, longestCommonSuffix, longestUncommonInfixes; transforming a string such as toBaseline, toSuperscript, toSubscript; transforming case of a string such as toKebabCase, toSnakeCase, toCamelCase, toPascalCase; finding ngrams in strings such as ngrams, uniqueNgrams, countNgrams, countUniqueNgrams, countEachNgram, matchingNgrams, uniqueMatchingNgrams, countMatchingNgrams, countEachMatchingNgram, countUniqueMatchingNgrams; and finding similarity/distance between strings such as euclideanDistance, hammingDistance, jaccardIndex, jaccardDistance, sorensenDiceIndex, sorensenDiceDistance, tverskyIndex, tverskyDistance, jaroSimilarity, jaroDistance, jaroWinklerSimilarity, jaroWinklerDistance, levenshteinDistance, damerauLevenshteinDistance.

This package also provides Array-like functions for strings. These includes functions for generating a string such as of, from; transforming a string such as splice, reverse, sort; and functional behavior such as filter. All built-in string functions are also included. Finally, constants for ASCII characters, and minimum/maximum code point are included.

This package is available in both Node.js and Web formats. The web format is exposed as extra_string standalone variable and can be loaded from jsDelivr CDN.

Stability: Experimental.

const string = require('extra-string');
// import * as string from "extra-string";
// import * as string from "https://unpkg.com/extra-string/index.mjs"; (deno)

string.longestCommonInfix('dismiss', 'mississipi');
// → 'miss'

string.longestUncommonInfixes('chocolatier', 'engineer');
// → ['chocolati', 'engine']

string.toKebabCase('Malwa Plateau');
// → 'malwa-plateau'

'6.626 x 10' + string.toSuperscript('-34');
// → '6.626 x 10⁻³⁴' (Planck's constant)

string.tverskyDistance('pikachu', 'raichu', 3, 0.2, 0.4);
// → 0.6666666666666667

• MDN Web docs
• Lodash documentation
• natural package by Chris Umbel and contributors
• esrever package by Mathias Bynens and contributors
• How do you reverse a string in-place in JavaScript?