Solid prism editor

Code editor component for SolidJS apps

What?

This is a rewrite of Prism code editor using Solid's signals. It's a lightweight, extensible code editor optimized for fast load times with many optional extensions.

Why?

I realized Prism code editor's architecture made a rewrite in SolidJS not only possible, but easy. The result is a component that behaves very similarly, while being easier to use inside SolidJS apps. If a full blown editor like CodeMirror or Monaco is overkill, this might just be the right fit.

Contents

• Installation
• Demo
• Examples
• Basic usage
• Props
• Extensions
  • Creating your own
• Editor API
  • Properties
    • DOM Elements
  • Methods
  • Signals
  • Extensions property
• Prism
• Languages
• Styling
  • Themes
• Performance
• Contributing

Installation

npm i solid-prism-editor

There's a peer dependency on solid-js (obviously).

Demo

Prism code editor's demo. There's no demo for this SolidJS rewrite since its behavior is nearly identical.

Examples

• Usage with SolidStart
• Usage in forms
• Tooltip example
• Relative line numbers
• Custom cursor

Basic usage

import { Editor } from "solid-prism-editor"
import { basicSetup } from "solid-prism-editor/setups"

// Adding the JSX grammar
import "solid-prism-editor/prism/languages/jsx"

// Adds comment toggling and auto-indenting for JSX
import "solid-prism-editor/languages/jsx"

import "solid-prism-editor/layout.css"
import "solid-prism-editor/themes/github-dark.css"

// Required by the basic setup
import "solid-prism-editor/search.css"

const MyEditor = () => (
  <Editor language="jsx" value="const foo = 'bar'" extensions={basicSetup} />
)

Props

Name	Type	Description
language	string	Language used for syntax highlighting. Defaults to text.
tabSize	number	Tab size used for indentation. Defaults to 2.
insertSpaces	boolean	Whether the editor should insert spaces for indentation. Defaults to true. Requires the defaultCommands() extension to work.
lineNumbers	boolean	Whether line numbers should be shown. Defaults to true.
readOnly	boolean	Whether the editor should be read only. Defaults to false.
wordWrap	boolean	Whether the editor should have word wrap. Defaults to false.
value	string	Initial value to display in the editor.
rtl	boolean	Whether the editor uses right to left directionality. Defaults to false. Requires extra CSS from solid-prism-editor/rtl-layout.css to work.
style	Omit<JSX.CSSProperties, "tab-size">	Inline styles for the container element
onMount	(editor: PrismEditor) => void	Callback used to access the underlying editor.
onUpdate	(value: string, editor: PrismEditor) => void	Function called after the editor updates.
onSelectionChange	(selection: InputSelection, value: string, editor: PrismEditor) => void	Function called when the editor's selection changes.
extensions	Extension[]	List of extensions added to the editor. More on extensions later.

Extensions

To keep the core light, most functionality is added by optional extensions.

There are extensions adding:

• Many common commands
• Bracket matching and rainbow brackets
• Tag matching
• Indentation guides
• Search, regex search and replace
• Selection match highlighting
• A copy button
• Read-only code folding
• Custom undo/redo
• And more...

Many commonly used extensions are added by basicSetup, but if you want to fully customize which extensions are added. Below it's shown how to import most extensions.

import { Editor } from "solid-prism-editor"
import "solid-prism-editor/prism/languages/jsx"
import "solid-prism-editor/layout.css"
// Needed for searchWidget()
import "solid-prism-editor/search.css"
// Needed for copyButton()
import "solid-prism-editor/copy-button.css"

import { matchBrackets } from "solid-prism-editor/match-brackets"
import { highlightBracketPairs } from "solid-prism-editor/highlight-brackets"
import { indentGuides } from "solid-prism-editor/guides"
import { highlightSelectionMatches, searchWidget } from "solid-prism-editor/search"
import { highlightMatchingTags, matchTags } from "solid-prism-editor/match-tags"
import { cursorPosition } from "solid-prism-editor/cursor"
import { defaultCommands, editHistory } from "solid-prism-editor/commands"
import { copyButton } from "solid-prism-editor/copy-button"
import { overscroll } from "solid-prism-editor/overscroll"

const MyEditor = () => {
  return (
    <Editor
      language="jsx"
      value="const foo = 'bar'"
      extensions={[
        matchBrackets(),
        searchWidget(),
        indentGuides(),
        highlightBracketPairs(),
        highlightSelectionMatches(),
        matchTags(),
        highlightMatchingTags(),
        cursorPosition(),
        defaultCommands(),
        editHistory(),
        copyButton(),
        overscroll(),
      ]}
    />
  )
}

If you make the extensions a signal, you can freely change which extensions are added to the editor. This makes it possible to asynchronously load most of the extensions to make your main JS bundle smaller. You can also remove extensions which currently isn't possible in Prism code editor.

import { createSignal } from "solid-js"
import { Editor } from "solid-prism-editor"
import { matchBrackets } from "solid-prism-editor/match-brackets"
import { indentGuides } from "solid-prism-editor/guides"
import { overscroll } from "solid-prism-editor/overscroll"

import "solid-prism-editor/prism/languages/jsx"
import "solid-prism-editor/layout.css"

const MyEditor = () => {
  const [extensions, setExtensions] = createSignal([matchBrackets(), indentGuides(), overscroll()])

  import("./extensions").then(mod => {
    setExtensions(e => e.concat(mod.extensions()))
  })

  return <Editor language="jsx" value="const foo = 'bar'" extensions={extensions()} />
}

// extensions.ts
import { highlightBracketPairs } from "solid-prism-editor/highlight-brackets"
import { highlightSelectionMatches, searchWidget } from "solid-prism-editor/search"
import { highlightMatchingTags, matchTags } from "solid-prism-editor/match-tags"
import { cursorPosition } from "solid-prism-editor/cursor"
import { defaultCommands, editHistory } from "solid-prism-editor/commands"
import { copyButton } from "solid-prism-editor/copy-button"

import "solid-prism-editor/search.css"
import "solid-prism-editor/copy-button.css"

export const extensions = () => [
  searchWidget(),
  highlightBracketPairs(),
  highlightSelectionMatches(),
  matchTags(),
  highlightMatchingTags(),
  cursorPosition(),
  defaultCommands(),
  editHistory(),
  copyButton(),
]

Creating your own

If you need to do anything more than adding a simple onUpdate or onSelectionChange callback, you should consider creating your own extension.

import { createEffect } from "solid-js"
import type { Extension } from "solid-prism-editor"

export const myExtension: Extension = (editor: PrismEditor) => {
  // Selection, tokens, focused and props on the editor are all reactive.
  createEffect(() => {
    console.log("New selection: ", editor.selection())
  })

  createEffect(() => {
    console.log("New tokens: ", editor.tokens())
  })

  createEffect(() => {
    console.log("New focus state: ", editor.focused())
  })

  createEffect(() => {
    console.log("New tab size: ", editor.props.tabSize || 2)
  })

  // The elements returned are added to the editor's overlays
  // Keep in mind that they will get some default styles
  return <div>My overlay</div>
}

Editor API

The editor object you can access with the onMount prop or by creating an extension has many useful properties and methods.

Properties

• value: string: Current value of the editor.
• activeLine: number: Line number of the line with the cursor. You can index into editor.lines to get the DOM node for the active line.
• inputCommandMap: Record<string, InputCommandCallback | null | undefined>: Record mapping an input to a function called when that input is typed.
• keyCommandMap: Record<string, KeyCommandCallback | null | undefined>: Record mapping KeyboardEvent.key to a function called when that key is pressed.
• extensions: Object: Object storing some of the extensions added to the editor. Read more.
• props: EditorProps: The component props passed to the editor. They are reactive like all props in SolidJS.

DOM Elements

• container: HTMLDivElement: This is the outermost element of the editor.
• wrapper: HTMLDivElement: Element wrapping the lines and overlays.
• lines: HTMLCollectionOf<HTMLDivElement>: Collection containing the overlays as the first element, followed by all code lines.
• textarea: HTMLTextAreaElement: Underlying textarea in the editor.

Methods

• update(): void: Forces the editor to update. Can be useful after modifying a grammar for example.
• getSelection(): InputSelection: Gets the selectionStart, selectionEnd and selectionDirection for the textarea.
• setSelection(start: number, end?: number, direction?: "backward" | "forward" | "none"): void: Sets the selection for the textarea and synchronously updates the selection signal.

Signals

• focused(): boolean: Reactive accessor for whether the textarea is focused. Effects depending on this property will run during focus or blur events on the textarea.
• tokens(): TokenStream: Reactive accessor for the current tokens. Computations depending on this property will run right before the tokens are converted to an HTML string.
• selection(): InputSelection: Reactive accessor for the current selection. Effects depending on this property will run after the syntax highlighting is finished or when the selection changes.

Extensions property

Multiple extensions have an entry on editor.extensions allowing you to interact with the extension.

• matchBrackets: BracketMatcher: Allows access to all brackets found in the editor along with which are paired together.
• matchTags: TagMatcher: Allows access to all tags found in the editor along with which tags are paired together.
• cursor: Cursor: Allows you to get the cursor position relative to the editor's overlays and to scroll the cursor into view.
• searchWidget: SearchWidget: Allows you to open or close the search widget.
• history: EditHistory: Allows you to clear the history or navigate it.
• folding: ReadOnlyCodeFolding: Allows access to the full unfolded code and to toggle folded ranges.

Prism

The Prism instance used by this library is exported from solid-prism-editor/prism. This allows you to add your own Prism grammars or perform syntax highlighting outside of an editor. All modules under solid-prism-editor/prism can run outside the browser in for example Node.js to do syntax highlighting on the server. API docs.

Languages

Prism supports syntax highlighting for hundreds of languages, but none of them are imported by default. You need to choose which languages to import. Importing solid-prism-editor/prism/languages/javascript for example will register the JavaScript grammar through side effects.

If you need access to many languages, you can import the following entry points:

• solid-prism-editor/prism/languages for all languages (~180kB)
• solid-prism-editor/prism/languages/common for 42 common languages (~30kB)

This library also supports auto-indenting, comment toggling and self-closing tags for most of these languages. For it to work, you need the defaultCommands() extension and to import the behavior for the language.

The easiest way is to import all languages at ~3.6kB gzipped. You can dynamically import this since it's usually not needed before the page has loaded.

import("solid-prism-editor/languages")

You can also import solid-prism-editor/languages/common instead to support a subset of common languages at less than 2kB gzipped.

Lastly, if you only need support for a few languages, you can do individual imports, for example solid-prism-editor/languages/html. Read more.

Styling

This library does not inject any CSS into the webpage, instead you must import them. If the default styles don't work for you, you can import your own styles instead.

• solid-prism-editor/layout.css is the layout for the editor.
• solid-prism-editor/scrollbar.css adds a custom scrollbar to desktop Chrome and Safari you can color with --editor__bg-scrollbar.
• solid-prism-editor/copy-button.css adds styling for the copyButton() extension.
• solid-prism-editor/search.css adds styling for the searchWidget() extension.
• solid-prism-editor/rtl-layout.css adds support for the rtl prop.

By default, the editor's height will fit the content, so you might want to add a height or max-height to .prism-code-editor depending on your use case.

Themes

here are currently 13 different themes you can import, one of them being from solid-prism-editor/themes/github-dark.css.

You can also dynamically import themes into your JavaScript.

import { loadTheme } from "solid-prism-editor/themes"

const isDark = matchMedia("(prefers-color-scheme: dark)").matches

loadTheme(isDark ? "github-dark" : "github-light").then(theme => {
  console.log(theme)
})

If none of the themes fit your website, use one of them as an example to help implement your own.

Performance

Manual DOM manipulation has been kept is almost every case. This rewrite therefore has very similar performance to the original.

Contributing

Contributions are welcome. To test your changes during development, run pnpm dev or npm run dev to run the test site.