Super Expressive is a JavaScript library that allows you to build regular expressions in almost natural language - with no extra dependencies, and a lightweight code footprint (less than 3kb with minification + gzip!).
-
Click to expand
- SuperExpressive()
- .allowMultipleMatches
- .lineByLine
- .caseInsensitive
- .sticky
- .unicode
- .singleLine
- .anyChar
- .whitespaceChar
- .nonWhitespaceChar
- .digit
- .nonDigit
- .word
- .nonWord
- .wordBoundary
- .nonWordBoundary
- .newline
- .carriageReturn
- .tab
- .nullByte
- .anyOf
- .capture
- .namedCapture(name)
- .backreference(index)
- .namedBackreference(index)
- .group
- .end()
- .assertAhead
- .assertNotAhead
- .optional
- .zeroOrMore
- .zeroOrMoreLazy
- .oneOrMore
- .oneOrMoreLazy
- .exactly(n)
- .atLeast(n)
- .between(x, y)
- .betweenLazy(x, y)
- .startOfInput
- .endOfInput
- .anyOfChars(chars)
- .anythingButChars(chars)
- .anythingButString(str)
- .anythingButRange(a, b)
- .string(s)
- .char(c)
- .range(a, b)
- .toRegexString()
- .toRegex()
Regex is a very powerful tool, but its terse and cryptic vocabulary can make constructing and communicating them with others a challenge. Even developers who understand them well can have trouble reading their own back just a few months later! In addition, they can't be easily created and manipulated in a programmatic way - closing off an entire avenue of dynamic text processing.
That's where Super Expressive comes in. It provides a programmatic and human readable way to create regular expressions. It's API uses the fluent builder pattern, and is completely immutable. It's built to be discoverable and predictable:
- properties and methods describe what they do in plain English
- order matters! quantifiers are specified before the thing they change, just like in English (e.g.
SuperExpressive().exactly(5).digit) - if you make a mistake, you'll know how to fix it. SuperExpressive will guide you towards a fix if your expression is invalid
SuperExpressive turns those complex and unweildy regexes that appear in code reviews into something that can be read, understood, and properly reviewed by your peers - and maintained by anyone!
npm i super-expressive
const SuperExpressive = require('super-expressive');The following example recognises and captures the value of a 16-bit hexadecmal number like 0xC0D3.
const SuperExpressive = require('super-expressive');
const myRegex = SuperExpressive()
.startOfInput
.optional.string('0x')
.capture
.exactly(4).anyOf
.range('A', 'F')
.range('a', 'f')
.range('0', '9')
.end()
.end()
.endOfInput
.toRegex();
// Produces the following regular expression:
/^(?:0x)?([A-Fa-f0-9]{4})$/SuperExpressive()
Creates an instance of SuperExpressive.
Uses the g flag on the regular expression, which indicates that it should match multiple values when run on a string.
Example
SuperExpressive()
.allowMultipleMatches
.string('hello')
.toRegex();
// ->
/hello/gUses the m flag on the regular expression, which indicates that it should treat the .startOfInput and .endOfInput markers as the start and end of lines.
Example
SuperExpressive()
.lineByLine
.string('^hello$')
.toRegex();
// ->
/\^hello\$/mUses the i flag on the regular expression, which indicates that it should treat ignore the uppercase/lowercase distinction when matching.
Example
SuperExpressive()
.caseInsensitive
.string('HELLO')
.toRegex();
// ->
/HELLO/iUses the y flag on the regular expression, which indicates that it should create a stateful regular expression that can be resumed from the last match.
Example
SuperExpressive()
.sticky
.string('hello')
.toRegex();
// ->
/hello/yUses the u flag on the regular expression, which indicates that it should use full unicode matching.
Example
SuperExpressive()
.unicode
.string('héllo')
.toRegex();
// ->
/héllo/uUses the s flag on the regular expression, which indicates that the input should be treated as a single line, where the .startOfInput and .endOfInput markers explicitly mark the start and end of input, and .anyChar also matches newlines.
Example
SuperExpressive()
.singleLine
.string('hello')
.anyChar
.string('world')
.toRegex();
// ->
/hello.world/sMatches any single character. When combined with .singleLine, it also matches newlines.
Example
SuperExpressive()
.anyChar
.toRegex();
// ->
/./Matches any whitespace character, including the special whitespace characters: \r\n\t\f\v.
Example
SuperExpressive()
.whitespaceChar
.toRegex();
// ->
/\s/Matches any non-whitespace character, excluding also the special whitespace characters: \r\n\t\f\v.
Example
SuperExpressive()
.nonWhitespaceChar
.toRegex();
// ->
/\S/Matches any digit from 0-9.
Example
SuperExpressive()
.digit
.toRegex();
// ->
/\d/Matches any non-digit.
Example
SuperExpressive()
.nonDigit
.toRegex();
// ->
/\D/Matches any alpha-numeric (a-z, A-Z, 0-9) characters, as well as _.
Example
SuperExpressive()
.word
.toRegex();
// ->
/\w/Matches any non alpha-numeric (a-z, A-Z, 0-9) characters, excluding _ as well.
Example
SuperExpressive()
.nonWord
.toRegex();
// ->
/\W/Matches (without consuming any characters) immediately between a character matched by .word and a character not matched by .word (in either order).
Example
SuperExpressive()
.digit
.wordBoundary
.toRegex();
// ->
/\d\b/Matches (without consuming any characters) at the position between two characters matched by .word.
Example
SuperExpressive()
.digit
.nonWordBoundary
.toRegex();
// ->
/\d\B/Matches a \n character.
Example
SuperExpressive()
.newline
.toRegex();
// ->
/\n/Matches a \r character.
Example
SuperExpressive()
.carriageReturn
.toRegex();
// ->
/\r/Matches a \t character.
Example
SuperExpressive()
.tab
.toRegex();
// ->
/\t/Matches a \u0000 character (ASCII 0).
Example
SuperExpressive()
.nullByte
.toRegex();
// ->
/\0/Matches a choice between specified elements. Needs to be finalised with .end().
Example
SuperExpressive()
.anyOf
.range('a', 'f')
.range('0', '9')
.string('XXX')
.end()
.toRegex();
// ->
/(?:XXX|[a-f0-9])/Creates a capture group for the proceeding elements. Needs to be finalised with .end(). Can be later referenced with backreference(index).
Example
SuperExpressive()
.capture
.range('a', 'f')
.range('0', '9')
.string('XXX')
.end()
.toRegex();
// ->
/([a-f][0-9]XXX)/Creates a named capture group for the proceeding elements. Needs to be finalised with .end(). Can be later referenced with namedBackreference(name) or backreference(index).
Example
SuperExpressive()
.namedCapture('interestingStuff')
.range('a', 'f')
.range('0', '9')
.string('XXX')
.end()
.toRegex();
// ->
/(?<interestingStuff>[a-f][0-9]XXX)/Matches exactly what was previously matched by a namedCapture.
Example
SuperExpressive()
.namedCapture('interestingStuff')
.range('a', 'f')
.range('0', '9')
.string('XXX')
.end()
.string('something else')
.namedBackreference('interestingStuff')
.toRegex();
// ->
/(?<interestingStuff>[a-f][0-9]XXX)something else\k<interestingStuff>/Matches exactly what was previously matched by a capture or namedCapture using a positional index. Note regex indexes start at 1, so the first capture group has index 1.
Example
SuperExpressive()
.capture
.range('a', 'f')
.range('0', '9')
.string('XXX')
.end()
.string('something else')
.backreference(1)
.toRegex();
// ->
/([a-f][0-9]XXX)something else\1/Creates a non-capturing group of the proceeding elements. Needs to be finalised with .end().
Example
SuperExpressive()
.optional.group
.range('a', 'f')
.range('0', '9')
.string('XXX')
.end()
.toRegex();
// ->
/(?:[a-f][0-9]XXX)?/Signifies the end of a SuperExpressive grouping, such as .anyOf, .group, or .capture.
Example
SuperExpressive()
.capture
.anyOf
.range('a', 'f')
.range('0', '9')
.string('XXX')
.end()
.end()
.toRegex();
// ->
/((?:XXX|[a-f0-9]))/Assert that the proceeding elements are found without consuming them. Needs to be finalised with .end().
Example
SuperExpressive()
.assertAhead
.range('a', 'f')
.end()
.range('a', 'z')
.toRegex();
// ->
/(?=[a-f])[a-z]/Assert that the proceeding elements are not found without consuming them. Needs to be finalised with .end().
Example
SuperExpressive()
.assertNotAhead
.range('a', 'f')
.end()
.range('g', 'z')
.toRegex();
// ->
/(?![a-f])[g-z]/Assert that the proceeding element may or may not be matched.
Example
SuperExpressive()
.optional.digit
.toRegex();
// ->
/\d?/Assert that the proceeding element may not be matched, or may be matched multiple times.
Example
SuperExpressive()
.zeroOrMore.digit
.toRegex();
// ->
/\d*/Assert that the proceeding element may not be matched, or may be matched multiple times, but as few times as possible.
Example
SuperExpressive()
.zeroOrMoreLazy.digit
.toRegex();
// ->
/\d*?/Assert that the proceeding element may be matched once, or may be matched multiple times.
Example
SuperExpressive()
.oneOrMore.digit
.toRegex();
// ->
/\d+/Assert that the proceeding element may be matched once, or may be matched multiple times, but as few times as possible.
Example
SuperExpressive()
.oneOrMoreLazy.digit
.toRegex();
// ->
/\d+?/Assert that the proceeding element will be matched exactly n times.
Example
SuperExpressive()
.exactly(5).digit
.toRegex();
// ->
/\d{5}/Assert that the proceeding element will be matched at least n times.
Example
SuperExpressive()
.atLeast(5).digit
.toRegex();
// ->
/\d{5,}/Assert that the proceeding element will be matched somewhere between x and y times.
Example
SuperExpressive()
.between(3, 5).digit
.toRegex();
// ->
/\d{3,5}/Assert that the proceeding element will be matched somewhere between x and y times, but as few times as possible.
Example
SuperExpressive()
.betweenLazy(3, 5).digit
.toRegex();
// ->
/\d{3,5}?/Assert the start of input, or the start of a line when .lineByLine is used.
Example
SuperExpressive()
.startOfInput
.string('hello')
.toRegex();
// ->
/^hello/Assert the end of input, or the end of a line when .lineByLine is used.
Example
SuperExpressive()
.string('hello')
.endOfInput
.toRegex();
// ->
/end$/Matches any of the characters in the provided string chars.
Example
SuperExpressive()
.anyOfChars('aeiou')
.toRegex();
// ->
/[aeiou]/Matches any character, except any of those in the provided string chars.
Example
SuperExpressive()
.anythingButChars('aeiou')
.toRegex();
// ->
/[^aeiou]/Matches any string the same length as str, except the characters sequentially defined in str.
Example
SuperExpressive()
.anythingButString('aeiou')
.toRegex();
// ->
/(?:[^a][^e][^i][^o][^u])/Matches any character, except those that would be captured by the .range specified by a and b.
Example
SuperExpressive()
.anythingButRange(0, 9)
.toRegex();
// ->
/[^0-9]/Matches the exact string s.
Example
SuperExpressive()
.string('hello')
.toRegex();
// ->
/hello/Matches the exact character c.
Example
SuperExpressive()
.char('x')
.toRegex();
// ->
/x/Matches any character that falls between a and b. Ordering is defined by a characters ASCII or unicode value.
Example
SuperExpressive()
.range('a', 'z')
.toRegex();
// ->
/[a-z]/Outputs a string representation of the regular expression that this SuperExpression models.
Example
SuperExpressive()
.allowMultipleMatches
.lineByLine
.startOfInput
.optional.string('0x')
.capture
.exactly(4).anyOf
.range('A', 'F')
.range('a', 'f')
.range('0', '9')
.end()
.end()
.endOfInput
.toRegexString();
// ->
"/^(?:0x)?([A-Fa-f0-9]{4})$/gm"Outputs the regular expression that this SuperExpression models.
Example
SuperExpressive()
.allowMultipleMatches
.lineByLine
.startOfInput
.optional.string('0x')
.capture
.exactly(4).anyOf
.range('A', 'F')
.range('a', 'f')
.range('0', '9')
.end()
.end()
.endOfInput
.toRegexString();
// ->
/^(?:0x)?([A-Fa-f0-9]{4})$/gm
React
Typescript
Django
Laravel
Facebook
Microsoft
Google
Alibaba
D3
Tencent