refractor
v4.8.1
Published
Lightweight, robust, elegant virtual syntax highlighting using Prism
Downloads
10,603,969
Maintainers
Readme
refractor
Lightweight, robust, elegant virtual syntax highlighting using Prism.
Contents
- What is this?
- When should I use this?
- Playground
- Install
- Use
- API
- Examples
- Types
- Data
- CSS
- Compatibility
- Security
- Related
- Projects
- Contribute
What is this?
This package wraps Prism to output objects (ASTs) instead of a string of HTML.
Prism, through refractor, supports 270+ programming languages. Supporting all of them requires a lot of code. That’s why there are three entry points for refractor:
lib/core.js
— 0 languageslib/common.js
(default) — 36 languageslib/all.js
— 297 languages
Bundled, minified, and gzipped, those are roughly 12.7 kB, 40 kB, and 211 kB.
When should I use this?
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 refractor 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).
A different package, lowlight
, does the same as refractor but
uses highlight.js
instead.
If you’re looking for a really good (but rather heavy) highlighter, try
starry-night
.
Playground
You can play with refractor on the interactive demo (Replit).
Install
This package is ESM only. In Node.js (version 14.14+, 16.0+), install with npm:
npm install refractor
In Deno with esm.sh
:
import {refractor} from 'https://esm.sh/refractor@4'
In browsers with esm.sh
:
<script type="module">
import {refractor} from 'https://esm.sh/refractor@4?bundle'
</script>
Use
import {refractor} from 'refractor'
const tree = refractor.highlight('"use strict";', 'js')
console.log(tree)
Yields:
{
type: 'root',
children: [
{
type: 'element',
tagName: 'span',
properties: {className: ['token', 'string']},
children: [{type: 'text', value: '"use strict"'}]
},
{
type: 'element',
tagName: 'span',
properties: {className: ['token', 'punctuation']},
children: [{type: 'text', value: ';'}]
}
]
}
API
This package exports the identifier refractor
.
There is no default export.
refractor.highlight(value, language)
Highlight value
(code) as language
(programming language).
Parameters
value
(string
) — code to highlightlanguage
(string
orGrammar
) — programming language name, alias, or grammar.
Returns
Node representing highlighted code (Root
).
Example
import {refractor} from 'refractor/lib/core.js'
import css from 'refractor/lang/css.js'
refractor.register(css)
console.log(refractor.highlight('em { color: red }', 'css'))
Yields:
{
type: 'root',
children: [
{type: 'element', tagName: 'span', properties: [Object], children: [Array]},
{type: 'text', value: ' '},
// …
{type: 'text', value: ' red '},
{type: 'element', tagName: 'span', properties: [Object], children: [Array]}
]
}
refractor.register(syntax)
Register a syntax.
Parameters
syntax
(Function
) — language function custom made for refractor, as in, the files inrefractor/lang/*.js
Example
import {refractor} from 'refractor/lib/core.js'
import markdown from 'refractor/lang/markdown.js'
refractor.register(markdown)
console.log(refractor.highlight('*Emphasis*', 'markdown'))
Yields:
{
type: 'root',
children: [
{type: 'element', tagName: 'span', properties: [Object], children: [Array]}
]
}
refractor.alias(name[, alias])
Register aliases for already registered languages.
Signatures
alias(name, alias|list)
alias(aliases)
Parameters
language
(string
) — programming language namealias
(string
) — new aliases for the programming languagelist
(Array<string>
) — list of aliasesaliases
(Record<language, alias|list>
) — map oflanguage
s toalias
es orlist
s
Example
import {refractor} from 'refractor/lib/core.js'
import markdown from 'refractor/lang/markdown.js'
refractor.register(markdown)
// refractor.highlight('*Emphasis*', 'mdown')
// ^ would throw: Error: Unknown language: `mdown` is not registered
refractor.alias({markdown: ['mdown', 'mkdn', 'mdwn', 'ron']})
refractor.highlight('*Emphasis*', 'mdown')
// ^ Works!
refractor.registered(aliasOrlanguage)
Check whether an alias
or language
is registered.
Parameters
aliasOrlanguage
(string
) — programming language name or alias
Example
import {refractor} from 'refractor/lib/core.js'
import markdown from 'refractor/lang/markdown.js'
console.log(refractor.registered('markdown')) //=> false
refractor.register(markdown)
console.log(refractor.registered('markdown')) //=> true
refractor.listLanguages()
List all registered languages (names and aliases).
Returns
Array<string>
.
Example
import {refractor} from 'refractor/lib/core.js'
import markdown from 'refractor/lang/markdown.js'
console.log(refractor.listLanguages()) //=> []
refractor.register(markdown)
console.log(refractor.listLanguages())
Yields:
[
'markup', // Note that `markup` (a lot of xml based languages) is a dep of markdown.
'html',
// …
'markdown',
'md'
]
Examples
Example: serializing hast as html
hast trees as returned by refractor can be serialized with
hast-util-to-html
:
import {refractor} from 'refractor'
import {toHtml} from 'hast-util-to-html'
const tree = refractor.highlight('"use strict";', 'js')
console.log(toHtml(tree))
Yields:
<span class="token string">"use strict"</span><span class="token punctuation">;</span>
Example: turning hast into react nodes
hast trees as returned by refractor can be turned into React (or Preact) with
hast-to-hyperscript
:
import {refractor} from 'refractor'
import {toH} from 'hast-to-hyperscript'
import React from 'react'
const tree = refractor.highlight('"use strict";', 'js')
const react = toH(React.createElement, tree)
console.log(react)
Yields:
{
'$$typeof': Symbol(react.element),
type: 'div',
key: 'h-1',
ref: null,
props: { children: [ [Object], [Object] ] },
_owner: null,
_store: {}
}
Types
This package is fully typed with TypeScript.
It exports the additional types Root
, Grammar
, and Syntax
.
Data
If you’re using refractor/lib/core.js
, no syntaxes are included.
Checked syntaxes are included if you import refractor
(or explicitly
refractor/lib/common.js
).
Unchecked syntaxes are available through refractor/lib/all.js
.
You can import core
or common
and manually add more languages as you please.
Prism operates as a singleton: once you register a language in one place, it’ll be available everywhere.
Only these custom built syntaxes will work with refractor
because Prism’s own
syntaxes are made to work with global variables and are not importable.
- [x]
arduino
— alias:ino
- [x]
bash
— alias:sh
,shell
- [x]
basic
- [x]
c
- [x]
clike
- [x]
cpp
- [x]
csharp
— alias:cs
,dotnet
- [x]
css
- [x]
diff
- [x]
go
- [x]
ini
- [x]
java
- [x]
javascript
— alias:js
- [x]
json
— alias:webmanifest
- [x]
kotlin
— alias:kt
,kts
- [x]
less
- [x]
lua
- [x]
makefile
- [x]
markdown
— alias:md
- [x]
markup
— alias:atom
,html
,mathml
,rss
,ssml
,svg
,xml
- [x]
markup-templating
- [x]
objectivec
— alias:objc
- [x]
perl
- [x]
php
- [x]
python
— alias:py
- [x]
r
- [x]
regex
- [x]
ruby
— alias:rb
- [x]
rust
- [x]
sass
- [x]
scss
- [x]
sql
- [x]
swift
- [x]
typescript
— alias:ts
- [x]
vbnet
- [x]
yaml
— alias:yml
- [ ]
abap
- [ ]
abnf
- [ ]
actionscript
- [ ]
ada
- [ ]
agda
- [ ]
al
- [ ]
antlr4
— alias:g4
- [ ]
apacheconf
- [ ]
apex
- [ ]
apl
- [ ]
applescript
- [ ]
aql
- [ ]
arff
- [ ]
armasm
— alias:arm-asm
- [ ]
arturo
— alias:art
- [ ]
asciidoc
— alias:adoc
- [ ]
asm6502
- [ ]
asmatmel
- [ ]
aspnet
- [ ]
autohotkey
- [ ]
autoit
- [ ]
avisynth
— alias:avs
- [ ]
avro-idl
— alias:avdl
- [ ]
awk
— alias:gawk
- [ ]
batch
- [ ]
bbcode
— alias:shortcode
- [ ]
bbj
- [ ]
bicep
- [ ]
birb
- [ ]
bison
- [ ]
bnf
— alias:rbnf
- [ ]
bqn
- [ ]
brainfuck
- [ ]
brightscript
- [ ]
bro
- [ ]
bsl
— alias:oscript
- [ ]
cfscript
— alias:cfc
- [ ]
chaiscript
- [ ]
cil
- [ ]
cilkc
— alias:cilk-c
- [ ]
cilkcpp
— alias:cilk
,cilk-cpp
- [ ]
clojure
- [ ]
cmake
- [ ]
cobol
- [ ]
coffeescript
— alias:coffee
- [ ]
concurnas
— alias:conc
- [ ]
cooklang
- [ ]
coq
- [ ]
crystal
- [ ]
cshtml
— alias:razor
- [ ]
csp
- [ ]
css-extras
- [ ]
csv
- [ ]
cue
- [ ]
cypher
- [ ]
d
- [ ]
dart
- [ ]
dataweave
- [ ]
dax
- [ ]
dhall
- [ ]
django
— alias:jinja2
- [ ]
dns-zone-file
— alias:dns-zone
- [ ]
docker
— alias:dockerfile
- [ ]
dot
— alias:gv
- [ ]
ebnf
- [ ]
editorconfig
- [ ]
eiffel
- [ ]
ejs
— alias:eta
- [ ]
elixir
- [ ]
elm
- [ ]
erb
- [ ]
erlang
- [ ]
etlua
- [ ]
excel-formula
— alias:xls
,xlsx
- [ ]
factor
- [ ]
false
- [ ]
firestore-security-rules
- [ ]
flow
- [ ]
fortran
- [ ]
fsharp
- [ ]
ftl
- [ ]
gap
- [ ]
gcode
- [ ]
gdscript
- [ ]
gedcom
- [ ]
gettext
— alias:po
- [ ]
gherkin
- [ ]
git
- [ ]
glsl
- [ ]
gml
— alias:gamemakerlanguage
- [ ]
gn
— alias:gni
- [ ]
go-module
— alias:go-mod
- [ ]
gradle
- [ ]
graphql
- [ ]
groovy
- [ ]
haml
- [ ]
handlebars
— alias:hbs
,mustache
- [ ]
haskell
— alias:hs
- [ ]
haxe
- [ ]
hcl
- [ ]
hlsl
- [ ]
hoon
- [ ]
hpkp
- [ ]
hsts
- [ ]
http
- [ ]
ichigojam
- [ ]
icon
- [ ]
icu-message-format
- [ ]
idris
— alias:idr
- [ ]
iecst
- [ ]
ignore
— alias:gitignore
,hgignore
,npmignore
- [ ]
inform7
- [ ]
io
- [ ]
j
- [ ]
javadoc
- [ ]
javadoclike
- [ ]
javastacktrace
- [ ]
jexl
- [ ]
jolie
- [ ]
jq
- [ ]
js-extras
- [ ]
js-templates
- [ ]
jsdoc
- [ ]
json5
- [ ]
jsonp
- [ ]
jsstacktrace
- [ ]
jsx
- [ ]
julia
- [ ]
keepalived
- [ ]
keyman
- [ ]
kumir
— alias:kum
- [ ]
kusto
- [ ]
latex
— alias:context
,tex
- [ ]
latte
- [ ]
lilypond
— alias:ly
- [ ]
linker-script
— alias:ld
- [ ]
liquid
- [ ]
lisp
— alias:elisp
,emacs
,emacs-lisp
- [ ]
livescript
- [ ]
llvm
- [ ]
log
- [ ]
lolcode
- [ ]
magma
- [ ]
mata
- [ ]
matlab
- [ ]
maxscript
- [ ]
mel
- [ ]
mermaid
- [ ]
metafont
- [ ]
mizar
- [ ]
mongodb
- [ ]
monkey
- [ ]
moonscript
— alias:moon
- [ ]
n1ql
- [ ]
n4js
— alias:n4jsd
- [ ]
nand2tetris-hdl
- [ ]
naniscript
— alias:nani
- [ ]
nasm
- [ ]
neon
- [ ]
nevod
- [ ]
nginx
- [ ]
nim
- [ ]
nix
- [ ]
nsis
- [ ]
ocaml
- [ ]
odin
- [ ]
opencl
- [ ]
openqasm
— alias:qasm
- [ ]
oz
- [ ]
parigp
- [ ]
parser
- [ ]
pascal
— alias:objectpascal
- [ ]
pascaligo
- [ ]
pcaxis
— alias:px
- [ ]
peoplecode
— alias:pcode
- [ ]
php-extras
- [ ]
phpdoc
- [ ]
plant-uml
— alias:plantuml
- [ ]
plsql
- [ ]
powerquery
— alias:mscript
,pq
- [ ]
powershell
- [ ]
processing
- [ ]
prolog
- [ ]
promql
- [ ]
properties
- [ ]
protobuf
- [ ]
psl
- [ ]
pug
- [ ]
puppet
- [ ]
pure
- [ ]
purebasic
— alias:pbfasm
- [ ]
purescript
— alias:purs
- [ ]
q
- [ ]
qml
- [ ]
qore
- [ ]
qsharp
— alias:qs
- [ ]
racket
— alias:rkt
- [ ]
reason
- [ ]
rego
- [ ]
renpy
— alias:rpy
- [ ]
rescript
— alias:res
- [ ]
rest
- [ ]
rip
- [ ]
roboconf
- [ ]
robotframework
— alias:robot
- [ ]
sas
- [ ]
scala
- [ ]
scheme
- [ ]
shell-session
— alias:sh-session
,shellsession
- [ ]
smali
- [ ]
smalltalk
- [ ]
smarty
- [ ]
sml
— alias:smlnj
- [ ]
solidity
— alias:sol
- [ ]
solution-file
— alias:sln
- [ ]
soy
- [ ]
sparql
— alias:rq
- [ ]
splunk-spl
- [ ]
sqf
- [ ]
squirrel
- [ ]
stan
- [ ]
stata
- [ ]
stylus
- [ ]
supercollider
— alias:sclang
- [ ]
systemd
- [ ]
t4-cs
— alias:t4
- [ ]
t4-templating
- [ ]
t4-vb
- [ ]
tap
- [ ]
tcl
- [ ]
textile
- [ ]
toml
- [ ]
tremor
— alias:trickle
,troy
- [ ]
tsx
- [ ]
tt2
- [ ]
turtle
— alias:trig
- [ ]
twig
- [ ]
typoscript
— alias:tsconfig
- [ ]
unrealscript
— alias:uc
,uscript
- [ ]
uorazor
- [ ]
uri
— alias:url
- [ ]
v
- [ ]
vala
- [ ]
velocity
- [ ]
verilog
- [ ]
vhdl
- [ ]
vim
- [ ]
visual-basic
— alias:vb
,vba
- [ ]
warpscript
- [ ]
wasm
- [ ]
web-idl
— alias:webidl
- [ ]
wgsl
- [ ]
wiki
- [ ]
wolfram
— alias:mathematica
,nb
,wl
- [ ]
wren
- [ ]
xeora
— alias:xeoracube
- [ ]
xml-doc
- [ ]
xojo
- [ ]
xquery
- [ ]
yang
- [ ]
zig
CSS
refractor
does not inject CSS for the syntax highlighted code (because well,
refractor 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 Prism theme.
For example, to get Prism Dark from cdnjs:
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/prism/1.27.0/themes/prism-dark.min.css">
Compatibility
This package is at least compatible with all maintained versions of Node.js. As of now, that is Node.js 14.14+ and 16.0+. It also works in Deno and modern browsers.
Only the custom built syntaxes in refractor/lang/*.js
will work with
refractor
as Prism’s own syntaxes are made to work with global variables and
are not importable.
refractor also does not support Prism plugins, due to the same limitations, and that they almost exclusively deal with the DOM.
Security
This package is safe.
Related
lowlight
— the same as refractor but withhighlight.js
starry-night
— similar but like GitHub and really good
Projects
react-syntax-highlighter
— React component for syntax highlighting@mapbox/rehype-prism
— rehype plugin to highlight code blocksreact-refractor
— syntax highlighter for React
Contribute
Yes please! See How to Contribute to Open Source.