Virtual syntax highlighting for virtual DOMs and non-HTML things
MIT License
Virtual syntax highlighting for virtual DOMs and non-HTML things based on
highlight.js
.
This package uses highlight.js
for syntax highlighting and
outputs objects (ASTs) instead of a string of HTML.
It can support 190+ programming languages.
This package is useful when you want to perform syntax highlighting in a place where serialized HTML wouldn’t work or wouldn’t work well. For example, you can use lowlight when you want to show code in a CLI by rendering to ANSI sequences, when you’re using virtual DOM frameworks (such as React or Preact) so that diffing can be performant, or when you’re working with ASTs (rehype).
You can use the similar refractor
if you want to use Prism
grammars instead.
If you’re looking for a really good (but rather heavy) alternative, use
starry-night
.
This package is ESM only. In Node.js (version 16+), install with npm:
npm install lowlight
In Deno with esm.sh
:
import {all, common, createLowlight} from 'https://esm.sh/lowlight@3'
In browsers with esm.sh
:
<script type="module">
import {all, common, createLowlight} from 'https://esm.sh/lowlight@3?bundle'
</script>
import {common, createLowlight} from 'lowlight'
const lowlight = createLowlight(common)
const tree = lowlight.highlight('js', '"use strict";')
console.dir(tree, {depth: undefined})
Yields:
{
type: 'root',
children: [
{
type: 'element',
tagName: 'span',
properties: {className: ['hljs-meta']},
children: [{type: 'text', value: '"use strict"'}]
},
{type: 'text', value: ';'}
],
data: {language: 'js', relevance: 10}
}
This package exports the identifiers all
,
common
, and
createLowlight
.
There is no default export.
all
Map of all (±190) grammars (Record<string, LanguageFn>
).
common
Map of common (37) grammars (Record<string, LanguageFn>
).
createLowlight([grammars])
Create a lowlight
instance.
grammars
(Record<string, LanguageFn>
, optional)Lowlight (Lowlight
).
lowlight.highlight(language, value[, options])
Highlight value
(code) as language
(name).
language
(string
)value
(string
)options
(Options
, optional)Tree (Root
); with the following data
fields: language
(string
), detected programming language name; relevance
(number
), how
sure lowlight is that the given code is in the language.
import {common, createLowlight} from 'lowlight'
const lowlight = createLowlight(common)
console.log(lowlight.highlight('css', 'em { color: red }'))
Yields:
{type: 'root', children: [Array], data: {language: 'css', relevance: 3}}
lowlight.highlightAuto(value[, options])
Highlight value
(code) and guess its programming language.
value
(string
)options
(AutoOptions
, optional)Tree (Root
); with the following data
fields: language
(string
), detected programming language name; relevance
(number
), how
sure lowlight is that the given code is in the language.
import {common, createLowlight} from 'lowlight'
const lowlight = createLowlight(common)
console.log(lowlight.highlightAuto('"hello, " + name + "!"'))
Yields:
{type: 'root', children: [Array], data: {language: 'arduino', relevance: 2}}
lowlight.listLanguages()
List registered languages.
Names of registered language (Array<string>
).
import {createLowlight} from 'lowlight'
import markdown from 'highlight.js/lib/languages/markdown'
const lowlight = createLowlight()
console.log(lowlight.listLanguages()) // => []
lowlight.register({markdown})
console.log(lowlight.listLanguages()) // => ['markdown']
lowlight.register(grammars)
Register languages.
register(name, grammar)
register(grammars)
name
(string
)grammar
(LanguageFn
)grammars
(Record<string, LanguageFn>
, optional)Nothing (undefined
).
import {createLowlight} from 'lowlight'
import xml from 'highlight.js/lib/languages/xml'
const lowlight = createLowlight()
lowlight.register({xml})
// Note: `html` is an alias for `xml`.
console.log(lowlight.highlight('html', '<em>Emphasis</em>'))
Yields:
{type: 'root', children: [Array], data: {language: 'html', relevance: 2}}
lowlight.registerAlias(aliases)
Register aliases.
registerAlias(aliases)
registerAlias(name, alias)
aliases
(Record<string, Array<string> | string>
)name
(string
)alias
(Array<string> | string
)Nothing (undefined
).
import {createLowlight} from 'lowlight'
import markdown from 'highlight.js/lib/languages/markdown'
const lowlight = createLowlight()
lowlight.register({markdown})
// lowlight.highlight('mdown', '<em>Emphasis</em>')
// ^ would throw: Error: Unknown language: `mdown` is not registered
lowlight.registerAlias({markdown: ['mdown', 'mkdn', 'mdwn', 'ron']})
lowlight.highlight('mdown', '<em>Emphasis</em>')
// ^ Works!
lowlight.registered(aliasOrlanguage)
Check whether an alias or name is registered.
aliasOrlanguage
(string
)Whether aliasOrName
is registered (boolean
).
import {createLowlight} from 'lowlight'
import javascript from 'highlight.js/lib/languages/javascript'
const lowlight = createLowlight({javascript})
console.log(lowlight.registered('funkyscript')) // => `false`
lowlight.registerAlias({javascript: 'funkyscript'})
console.log(lowlight.registered('funkyscript')) // => `true`
AutoOptions
Configuration for highlightAuto
(TypeScript type).
prefix
(string
, default: 'hljs-'
)subset
(Array<string>
, default: all registered languages)LanguageFn
Highlight.js grammar (TypeScript type).
type {LanguageFn} from 'highlight.js'
Options
Configuration for highlight
(TypeScript type).
prefix
(string
, default: 'hljs-'
)hast trees as returned by lowlight can be serialized with
hast-util-to-html
:
import {common, createLowlight} from 'lowlight'
import {toHtml} from 'hast-util-to-html'
const lowlight = createLowlight(common)
const tree = lowlight.highlight('js', '"use strict";')
console.log(toHtml(tree))
Yields:
<span class="hljs-meta">"use strict"</span>;
hast trees as returned by lowlight can be turned into nodes of any framework
that supports JSX, such as preact, react, solid, svelte, vue, and more, with
hast-util-to-jsx-runtime
:
import {toJsxRuntime} from 'hast-util-to-jsx-runtime'
// @ts-expect-error: react types don’t type these.
import {Fragment, jsx, jsxs} from 'react/jsx-runtime'
import {common, createLowlight} from 'lowlight'
const lowlight = createLowlight(common)
const tree = lowlight.highlight('js', '"use strict";')
console.log(toJsxRuntime(tree, {Fragment, jsx, jsxs}))
Yields:
{
$$typeof: Symbol(react.element),
type: Symbol(react.fragment),
key: null,
ref: null,
props: {children: [[Object], ';']},
_owner: null,
_store: {}
}
This package is fully typed with TypeScript.
It exports the additional types
AutoOptions
,
LanguageFn
, and
Options
.
It also registers root.data
with @types/hast
.
If you’re working with the data fields, make sure to import this package
somewhere in your types, as that registers the new fields on the file.
/**
* @import {Root} from 'hast'
* @import {} from 'lowlight'
*/
import {VFile} from 'vfile'
/** @type {Root} */
const root = {type: 'root', children: []}
console.log(root.data?.language) //=> TS now knows that this is a `string?`.
If you’re using createLowlight()
, no syntaxes are included yet.
You can import all
or common
and pass them, such as with
createLowlight(all)
.
Checked syntaxes are included in common
.
All syntaxes are included in all
.
You can also manually import syntaxes from highlight.js/lib/languages/xxx
,
where xxx
is the name, such as 'highlight.js/lib/languages/wasm'
.
1c
— 1C:Enterpriseabnf
— Augmented Backus-Naur Formaccesslog
— Apache Access Logactionscript
(as
) — ActionScriptada
— Adaangelscript
(asc
) — AngelScriptapache
(apacheconf
) — Apache configapplescript
(osascript
) — AppleScriptarcade
— ArcGIS Arcadearduino
(ino
) — Arduinoarmasm
(arm
) — ARM Assemblyasciidoc
(adoc
) — AsciiDocaspectj
— AspectJautohotkey
(ahk
) — AutoHotkeyautoit
— AutoItavrasm
— AVR Assemblyawk
— Awkaxapta
(x++
) — X++bash
(sh
, zsh
) — Bashbasic
— BASICbnf
— Backus–Naur Formbrainfuck
(bf
) — Brainfuckc
(h
) — Ccal
— C/ALcapnproto
(capnp
) — Cap’n Protoceylon
— Ceylonclean
(icl
, dcl
) — Cleanclojure
(clj
, edn
) — Clojureclojure-repl
— Clojure REPLcmake
(cmake.in
) — CMakecoffeescript
(coffee
, cson
, iced
) — CoffeeScriptcoq
— Coqcos
(cls
) — Caché Object Scriptcpp
(cc
, c++
, h++
, hpp
, hh
, hxx
, cxx
) — C++crmsh
(crm
, pcmk
) — crmshcrystal
(cr
) — Crystalcsharp
(cs
, c#
) — C#csp
— CSPcss
— CSSd
— Ddart
— Dartdelphi
(dpr
, dfm
, pas
, pascal
) — Delphidiff
(patch
) — Diffdjango
(jinja
) — Djangodns
(bind
, zone
) — DNS Zonedockerfile
(docker
) — Dockerfiledos
(bat
, cmd
) — Batch file (DOS)dsconfig
— undefineddts
— Device Treedust
(dst
) — Dustebnf
— Extended Backus-Naur Formelixir
(ex
, exs
) — Elixirelm
— Elmerb
— ERBerlang
(erl
) — Erlangerlang-repl
— Erlang REPLexcel
(xlsx
, xls
) — Excel formulaefix
— FIXflix
— Flixfortran
(f90
, f95
) — Fortranfsharp
(fs
, f#
) — F#gams
(gms
) — GAMSgauss
(gss
) — GAUSSgcode
(nc
) — G-code (ISO 6983)gherkin
(feature
) — Gherkinglsl
— GLSLgml
— GMLgo
(golang
) — Gogolo
— Gologradle
— Gradlegraphql
(gql
) — GraphQLgroovy
— Groovyhaml
— HAMLhandlebars
(hbs
, html.hbs
, html.handlebars
, htmlbars
) — Handlebarshaskell
(hs
) — Haskellhaxe
(hx
) — Haxehsp
— HSPhttp
(https
) — HTTPhy
(hylang
) — Hyinform7
(i7
) — Inform 7ini
(toml
) — TOML, also INIirpf90
— IRPF90isbl
— ISBLjava
(jsp
) — Javajavascript
(js
, jsx
, mjs
, cjs
) — JavaScriptjboss-cli
(wildfly-cli
) — JBoss CLIjson
(jsonc
) — JSONjulia
— Juliajulia-repl
(jldoctest
) — Julia REPLkotlin
(kt
, kts
) — Kotlinlasso
(ls
, lassoscript
) — Lassolatex
(tex
) — LaTeXldif
— LDIFleaf
— Leafless
— Lesslisp
— Lisplivecodeserver
— LiveCodelivescript
(ls
) — LiveScriptllvm
— LLVM IRlsl
— LSL (Linden Scripting Language)lua
— Luamakefile
(mk
, mak
, make
) — Makefilemarkdown
(md
, mkdown
, mkd
) — Markdownmathematica
(mma
, wl
) — Mathematicamatlab
— Matlabmaxima
— Maximamel
— MELmercury
(m
, moo
) — Mercurymipsasm
(mips
) — MIPS Assemblymizar
— Mizarmojolicious
— Mojoliciousmonkey
— Monkeymoonscript
(moon
) — MoonScriptn1ql
— N1QLnestedtext
(nt
) — Nested Textnginx
(nginxconf
) — Nginx confignim
— Nimnix
(nixos
) — Nixnode-repl
— Node REPLnsis
— NSISobjectivec
(mm
, objc
, obj-c
, obj-c++
, objective-c++
) — Objective-Cocaml
(ml
) — OCamlopenscad
(scad
) — OpenSCADoxygene
— Oxygeneparser3
— Parser3perl
(pl
, pm
) — Perlpf
(pf.conf
) — Packet Filter configpgsql
(postgres
, postgresql
) — PostgreSQLphp
— undefinedphp-template
— PHP templateplaintext
(text
, txt
) — Plain textpony
— Ponypowershell
(pwsh
, ps
, ps1
) — PowerShellprocessing
(pde
) — Processingprofile
— Python profilerprolog
— Prologproperties
— .propertiesprotobuf
(proto
) — Protocol Bufferspuppet
(pp
) — Puppetpurebasic
(pb
, pbi
) — PureBASICpython
(py
, gyp
, ipython
) — Pythonpython-repl
(pycon
) — undefinedq
(k
, kdb
) — Qqml
(qt
) — QMLr
— Rreasonml
(re
) — ReasonMLrib
— RenderMan RIBroboconf
(graph
, instances
) — Roboconfrouteros
(mikrotik
) — MikroTik RouterOS scriptrsl
— RenderMan RSLruby
(rb
, gemspec
, podspec
, thor
, irb
) — Rubyruleslanguage
— Oracle Rules Languagerust
(rs
) — Rustsas
— SASscala
— Scalascheme
(scm
) — Schemescilab
(sci
) — Scilabscss
— SCSSshell
(console
, shellsession
) — Shell Sessionsmali
— Smalismalltalk
(st
) — Smalltalksml
(ml
) — SML (Standard ML)sqf
— SQFsql
— SQLstan
(stanfuncs
) — Stanstata
(do
, ado
) — Statastep21
(p21
, step
, stp
) — STEP Part 21stylus
(styl
) — Stylussubunit
— SubUnitswift
— Swifttaggerscript
— Tagger Scripttap
— Test Anything Protocoltcl
(tk
) — Tclthrift
— Thrifttp
— TPtwig
(craftcms
) — Twigtypescript
(ts
, tsx
, mts
, cts
) — TypeScriptvala
— Valavbnet
(vb
) — Visual Basic .NETvbscript
(vbs
) — VBScriptvbscript-html
— VBScript in HTMLverilog
(v
, sv
, svh
) — Verilogvhdl
— VHDLvim
— Vim Scriptwasm
— WebAssemblywren
— Wrenx86asm
— Intel x86 Assemblyxl
(tao
) — XLxml
(html
, xhtml
, rss
, atom
, xjb
, xsd
, xsl
, plist
, wsf
, svg
) — HTML, XMLxquery
(xpath
, xq
, xqm
) — XQueryyaml
(yml
) — YAMLzephir
(zep
) — Zephirlowlight
does not inject CSS for the syntax highlighted code (because well,
lowlight doesn’t have to be turned into HTML and might not run in a browser!).
If you are in a browser, you can use any highlight.js
theme.
For example, to get GitHub Dark from cdnjs:
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/highlight.js/11.10.0/styles/github-dark.min.css">
This package is compatible with maintained versions of Node.js.
When we cut a new major release, we drop support for unmaintained versions of
Node.
This means we try to keep the current release line,
lowlight@^3
, compatible with Node.js 16.
This package is safe.
refractor
starry-night
emphasize
react-lowlight
react-syntax-highlighter
rehype-highlight
jstransformer-lowlight
Yes please! See How to Contribute to Open Source.