extra-string

A collection of common string functions. 📦 [Node.js](https://www.npmjs.com/package/extra-string), 🌐 [Web](https://www.npmjs.com/package/extra-string.web), 📜 [Files](https://unpkg.com/extra-string/), 📰 [Docs](https://nodef.github.io/extra-string/). 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]. [string]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String [mutable]: https://developer.mozilla.org/en-US/docs/Glossary/Mutable [jsDelivr CDN]: https://cdn.jsdelivr.net/npm/extra-string.web/index.js > Stability: [Experimental](https://www.youtube.com/watch?v=L1j93RnIxEo). ```javascript 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 ``` ## Index | Property | Description | | ---- | ---- | | [DIGITS] | Decimal digits 0-9. | | [OCT_DIGITS] | Octal digits 0-7. | | [HEX_DIGITS] | Hexadecimal digits 0-9, A-F, a-f. | | [UPPERCASE] | English letters A-Z. | | [LOWERCASE] | English letters a-z. | | [LETTERS] | Combination of uppercase, lowercase english letters. | | [PUNCTUATION] | Punctuation symbols (ASCII). | | [WHITESPACE] | The string "\t\n\x0b\x0c\r ". | | [PRINTABLE] | Combination of digits, letters, punctuation, and whitespace (ASCII). | | [MIN_CODE_POINT] | Minimum unicode code point. | | [MAX_CODE_POINT] | Maximum unicode code point. | | | | | [fromCharCode] | Get characters whose UTF-16 code units are given. | | [fromCodePoint] | Get characters whose unicode code points are given. | | [concat] | Combine multiple strings into one. | | [repeat] | Repeat string given number of times. | | | | | [valueOf] | Get primitive value of string object. | | [length] | Get length of string. | | [charAt] | Get character at given index in string. | | [charCodeAt] | Get UTF-16 code unit of a character in string. | | [codePointAt] | Get unicode code point of a character in string. | | | | | [localeCompare] | Compare two strings in the current or given locale. | | | | | [includes] | Check if string has a given infix. | | [startsWith] | Check if string has a given prefix. | | [endsWith] | Check if string has a given suffix. | | [indexOf] | Get first index of a given infix in string. | | [lastIndexOf] | Get last index of a given infix in string. | | [search] | Get first index of regular expression match in string. | | [match] | Get results of matching string with regular expression. | | [matchAll] | Get detailed results of matching string with regular expression. | | | | | [toString] | Get string representation of string. | | | | | [slice] | Extract section of string. | | [substring] | Extract section of string. | | [split] | Split string by a given separator into substrings. | | | | | [trimStart] | Remove whitespace from begining of string. | | [trimEnd] | Remove whitespace from end of string. | | [trim] | Remove whitespace from begining and end of string. | | [padStart] | Pad start of string to fit a desired length. | | [padEnd] | Pad end of string to fit a desired length. | | | | | [toUpperCase] | Convert string to upper case. | | [toLocaleUpperCase] | Convert string to upper case, as per locale-specific case mappings. | | [toLowerCase] | Convert string to lower case. | | [toLocaleLowerCase] | Convert string to lower case, as per locale-specific case mappings. | | | | | [replace] | Replace first match of given pattern by replacement. | | [normalize] | Normalize string by given form, as per Unicode Standard Annex #15. | | | | | [of] | Create string from arguments, like `Array.of()`. | | [from] | Create string from iterable, like `Array.from()`. | | | | | [splice] | Remove/replace characters in a string. | | [reverse] | Reverse a string. | | [sort] | Arrange characters in an order. | | | | | [filter] | Filter characters which pass a test. | | | | | [spaces] | Get a string of spaces. | | | | | [is] | Check if value is a string. | | [isEmpty] | Check if string is empty. | | [isCharacter] | Check if string is a character. | | [index] | Get non-negative index within string. | | [indexRange] | Get non-negative index range within string. | | [codePointRange] | Get unicode code point range of string. | | | | | [compare] | Compare two strings. | | [isEqual] | Check if two strings are equal. | | | | | [get] | Get character at a given index in string. | | [getAll] | Get characters at indices. | | [set] | Write a substring at specified index in string. | | [begin] | Get leftmost part of string. | | [middle] | Get a portion of string from middle. | | [end] | Get rightmost part of string. | | | | | [longestCommonInfix] | Get the longest common infix between strings. | | [longestCommonPrefix] | Get the longest common prefix of strings. | | [longestCommonSuffix] | Get the longest common suffix of strings. | | [longestUncommonInfixes] | Get the longest uncommon infixes of strings. | | | | | [toBaseline] | Convert a string to baseline characters (limited support). | | [toSuperscript] | Convert a string to superscript characters (limited support). | | [toSubscript] | Convert a string to superscript characters (limited support). | | | | | [toKebabCase] | Convert a string to kebab-case. | | [toSnakeCase] | Convert a string to snake-case. | | [toCamelCase] | Convert a string to camel-case. | | [toPascalCase] | Convert a string to pascal-case. | | | | | [ngrams] | Get n-grams of a string. | | [uniqueNgrams] | Find unique n-grams of a string. | | [countNgrams] | Count the total number of n-grams of a string. | | [countUniqueNgrams] | Count the total number of unique n-grams of a string. | | [countEachNgram] | Count each n-gram of a string. | | [matchingNgrams] | Get matching n-grams between strings. | | [uniqueMatchingNgrams] | Get unique matching n-grams between strings. | | [countMatchingNgrams] | Count the total number of matching n-grams between strings. | | [countEachMatchingNgram] | Count each matching n-gram between strings. | | [countUniqueMatchingNgrams] | Count the total number of unique matching n-grams between strings. | | | | | [euclideanDistance] | Get euclidean distance between strings. | | [hammingDistance] | Get hamming distance between strings. | | [jaccardIndex] | Get jaccard index between strings. | | [jaccardDistance] | Get jaccard distance between strings. | | [sorensenDiceIndex] | Get Sørensen-Dice index between strings. | | [sorensenDiceDistance] | Get Sørensen-Dice distance between strings. | | [tverskyIndex] | Get Tversky index between strings. | | [tverskyDistance] | Get Tversky distance between strings. | | [jaroSimilarity] | Get Jaro similarity between strings. | | [jaroDistance] | Get Jaro distance between strings. | | [jaroWinklerSimilarity] | Get Jaro-Winkler similarity between strings. | | [jaroWinklerDistance] | Get Jaro-Winkler distance between strings. | | [levenshteinDistance] | Get Levenshtein distance between strings. | | [damerauLevenshteinDistance] | Get Damerau–Levenshtein distance between strings. | ## References - [MDN Web docs](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference) - [Lodash documentation](https://lodash.com/docs/4.17.15) - [natural package by Chris Umbel and contributors](https://www.npmjs.com/package/natural) - [esrever package by Mathias Bynens and contributors](https://www.npmjs.com/package/esrever) - [js-string-compression package by Chen Caishun](https://github.com/cschen1205/js-string-compression) - [@stdlib/string-base-trim package by @stdlib-js](https://github.com/stdlib-js/string-base-trim) - [How do you reverse a string in-place in JavaScript?](https://stackoverflow.com/a/959004/1413259) [![](https://img.youtube.com/vi/zi0w7J7MCrk/maxresdefault.jpg)](https://www.youtube.com/watch?v=zi0w7J7MCrk) [![ORG](https://img.shields.io/badge/org-nodef-green?logo=Org)](https://nodef.github.io) [![DOI](https://zenodo.org/badge/149915096.svg)](https://zenodo.org/badge/latestdoi/149915096) [![Coverage Status](https://coveralls.io/repos/github/nodef/extra-string/badge.svg?branch=master)](https://coveralls.io/github/nodef/extra-string?branch=master) [![Test Coverage](https://api.codeclimate.com/v1/badges/1d8fb20d076d49a0f671/test_coverage)](https://codeclimate.com/github/nodef/extra-string/test_coverage) [![Maintainability](https://api.codeclimate.com/v1/badges/1d8fb20d076d49a0f671/maintainability)](https://codeclimate.com/github/nodef/extra-string/maintainability) ![](https://ga-beacon.deno.dev/G-RC63DPBH3P:SH3Eq-NoQ9mwgYeHWxu7cw/github.com/nodef/extra-string) [DIGITS]: https://nodef.github.io/extra-string/modules.html#DIGITS [OCT_DIGITS]: https://nodef.github.io/extra-string/modules.html#OCT_DIGITS [HEX_DIGITS]: https://nodef.github.io/extra-string/modules.html#HEX_DIGITS [UPPERCASE]: https://nodef.github.io/extra-string/modules.html#UPPERCASE [LOWERCASE]: https://nodef.github.io/extra-string/modules.html#LOWERCASE [LETTERS]: https://nodef.github.io/extra-string/modules.html#LETTERS [PUNCTUATION]: https://nodef.github.io/extra-string/modules.html#PUNCTUATION [WHITESPACE]: https://nodef.github.io/extra-string/modules.html#WHITESPACE [PRINTABLE]: https://nodef.github.io/extra-string/modules.html#PRINTABLE [MIN_CODE_POINT]: https://nodef.github.io/extra-string/modules.html#MIN_CODE_POINT [MAX_CODE_POINT]: https://nodef.github.io/extra-string/modules.html#MAX_CODE_POINT [fromCharCode]: https://nodef.github.io/extra-string/modules.html#fromCharCode [fromCodePoint]: https://nodef.github.io/extra-string/modules.html#fromCodePoint [concat]: https://nodef.github.io/extra-string/modules.html#concat [repeat]: https://nodef.github.io/extra-string/modules.html#repeat [valueOf]: https://nodef.github.io/extra-string/modules.html#valueOf [length]: https://nodef.github.io/extra-string/modules.html#length [charAt]: https://nodef.github.io/extra-string/modules.html#charAt [charCodeAt]: https://nodef.github.io/extra-string/modules.html#charCodeAt [codePointAt]: https://nodef.github.io/extra-string/modules.html#codePointAt [localeCompare]: https://nodef.github.io/extra-string/modules.html#localeCompare [includes]: https://nodef.github.io/extra-string/modules.html#includes [startsWith]: https://nodef.github.io/extra-string/modules.html#startsWith [endsWith]: https://nodef.github.io/extra-string/modules.html#endsWith [indexOf]: https://nodef.github.io/extra-string/modules.html#indexOf [lastIndexOf]: https://nodef.github.io/extra-string/modules.html#lastIndexOf [search]: https://nodef.github.io/extra-string/modules.html#search [match]: https://nodef.github.io/extra-string/modules.html#match [matchAll]: https://nodef.github.io/extra-string/modules.html#matchAll [toString]: https://nodef.github.io/extra-string/modules.html#toString [slice]: https://nodef.github.io/extra-string/modules.html#slice [substring]: https://nodef.github.io/extra-string/modules.html#substring [split]: https://nodef.github.io/extra-string/modules.html#split [trimStart]: https://nodef.github.io/extra-string/modules.html#trimStart [trimEnd]: https://nodef.github.io/extra-string/modules.html#trimEnd [trim]: https://nodef.github.io/extra-string/modules.html#trim [padStart]: https://nodef.github.io/extra-string/modules.html#padStart [padEnd]: https://nodef.github.io/extra-string/modules.html#padEnd [toUpperCase]: https://nodef.github.io/extra-string/modules.html#toUpperCase [toLocaleUpperCase]: https://nodef.github.io/extra-string/modules.html#toLocaleUpperCase [toLowerCase]: https://nodef.github.io/extra-string/modules.html#toLowerCase [toLocaleLowerCase]: https://nodef.github.io/extra-string/modules.html#toLocaleLowerCase [replace]: https://nodef.github.io/extra-string/modules.html#replace [normalize]: https://nodef.github.io/extra-string/modules.html#normalize [of]: https://nodef.github.io/extra-string/modules.html#of [from]: https://nodef.github.io/extra-string/modules.html#from [splice]: https://nodef.github.io/extra-string/modules.html#splice [reverse]: https://nodef.github.io/extra-string/modules.html#reverse [sort]: https://nodef.github.io/extra-string/modules.html#sort [filter]: https://nodef.github.io/extra-string/modules.html#filter [spaces]: https://nodef.github.io/extra-string/modules.html#spaces [is]: https://nodef.github.io/extra-string/modules.html#is [isEmpty]: https://nodef.github.io/extra-string/modules.html#isEmpty [isCharacter]: https://nodef.github.io/extra-string/modules.html#isCharacter [index]: https://nodef.github.io/extra-string/modules.html#index [indexRange]: https://nodef.github.io/extra-string/modules.html#indexRange [codePointRange]: https://nodef.github.io/extra-string/modules.html#codePointRange [compare]: https://nodef.github.io/extra-string/modules.html#compare [isEqual]: https://nodef.github.io/extra-string/modules.html#isEqual [get]: https://nodef.github.io/extra-string/modules.html#get [getAll]: https://nodef.github.io/extra-string/modules.html#getAll [set]: https://nodef.github.io/extra-string/modules.html#set [begin]: https://nodef.github.io/extra-string/modules.html#begin [middle]: https://nodef.github.io/extra-string/modules.html#middle [end]: https://nodef.github.io/extra-string/modules.html#end [longestCommonInfix]: https://nodef.github.io/extra-string/modules.html#longestCommonInfix [longestCommonPrefix]: https://nodef.github.io/extra-string/modules.html#longestCommonPrefix [longestCommonSuffix]: https://nodef.github.io/extra-string/modules.html#longestCommonSuffix [longestUncommonInfixes]: https://nodef.github.io/extra-string/modules.html#longestUncommonInfixes [toBaseline]: https://nodef.github.io/extra-string/modules.html#toBaseline [toSuperscript]: https://nodef.github.io/extra-string/modules.html#toSuperscript [toSubscript]: https://nodef.github.io/extra-string/modules.html#toSubscript [toKebabCase]: https://nodef.github.io/extra-string/modules.html#toKebabCase [toSnakeCase]: https://nodef.github.io/extra-string/modules.html#toSnakeCase [toCamelCase]: https://nodef.github.io/extra-string/modules.html#toCamelCase [toPascalCase]: https://nodef.github.io/extra-string/modules.html#toPascalCase [ngrams]: https://nodef.github.io/extra-string/modules.html#ngrams [uniqueNgrams]: https://nodef.github.io/extra-string/modules.html#uniqueNgrams [countNgrams]: https://nodef.github.io/extra-string/modules.html#countNgrams [countUniqueNgrams]: https://nodef.github.io/extra-string/modules.html#countUniqueNgrams [countEachNgram]: https://nodef.github.io/extra-string/modules.html#countEachNgram [matchingNgrams]: https://nodef.github.io/extra-string/modules.html#matchingNgrams [uniqueMatchingNgrams]: https://nodef.github.io/extra-string/modules.html#uniqueMatchingNgrams [countMatchingNgrams]: https://nodef.github.io/extra-string/modules.html#countMatchingNgrams [countEachMatchingNgram]: https://nodef.github.io/extra-string/modules.html#countEachMatchingNgram [countUniqueMatchingNgrams]: https://nodef.github.io/extra-string/modules.html#countUniqueMatchingNgrams [euclideanDistance]: https://nodef.github.io/extra-string/modules.html#euclideanDistance [hammingDistance]: https://nodef.github.io/extra-string/modules.html#hammingDistance [jaccardIndex]: https://nodef.github.io/extra-string/modules.html#jaccardIndex [jaccardDistance]: https://nodef.github.io/extra-string/modules.html#jaccardDistance [sorensenDiceIndex]: https://nodef.github.io/extra-string/modules.html#sorensenDiceIndex [sorensenDiceDistance]: https://nodef.github.io/extra-string/modules.html#sorensenDiceDistance [tverskyIndex]: https://nodef.github.io/extra-string/modules.html#tverskyIndex [tverskyDistance]: https://nodef.github.io/extra-string/modules.html#tverskyDistance [jaroSimilarity]: https://nodef.github.io/extra-string/modules.html#jaroSimilarity [jaroDistance]: https://nodef.github.io/extra-string/modules.html#jaroDistance [jaroWinklerSimilarity]: https://nodef.github.io/extra-string/modules.html#jaroWinklerSimilarity [jaroWinklerDistance]: https://nodef.github.io/extra-string/modules.html#jaroWinklerDistance [levenshteinDistance]: https://nodef.github.io/extra-string/modules.html#levenshteinDistance [damerauLevenshteinDistance]: https://nodef.github.io/extra-string/modules.html#damerauLevenshteinDistance