chatgpt-codemirror-theme.md

Code Edit

notebook.json

{
  "bundleFiles": [
    ["codemirror-bundle.md", "codemirror-bundle.js"]
  ]
}

This sets up CodeMirror. It supports getting and setting the text, and sends the code-input event when the text is edited. The filetype can be changed dynamically.

code-edit.js

const {tags} = window.CodeMirrorModules['@lezer/highlight'];
const {HighlightStyle} = window.CodeMirrorModules['@codemirror/language'];
const {EditorView} = window.CodeMirrorModules['@codemirror/view'];

const myTheme = EditorView.theme({
  "&": {
    color: "#FFFF33", // Bright yellow text
    backgroundColor: "#FF6600", // Bright orange background
  },
  ".cm-content": {
    caretColor: "#FFFF33", // Bright yellow caret
  },
  "&.cm-focused .cm-cursor": {
    borderLeftColor: "#FFFF33", // Bright yellow cursor
  },
  "&.cm-focused .cm-selectionBackground, .cm-selectionBackground, ::selection": {
    backgroundColor: "#FF9933", // Light orange selection background
  },
  ".cm-activeLine": {
    backgroundColor: "#FF8533", // Slightly darker orange for active line
  },
  ".cm-gutters": {
    backgroundColor: "#FF6600", // Bright orange background for gutters
    color: "#FFFF66", // Bright yellow for line numbers
    border: "none",
  },
  ".cm-tooltip": {
    border: "1px solid #FFFF66",
    backgroundColor: "#FF6600",
    color: "#FFFF33",
  },
  ".cm-tooltip.cm-tooltip-autocomplete": {
    "& > ul > li[aria-selected]": {
      backgroundColor: "#FF8533",
      color: "#FFFF33",
    },
  },
}, {dark: true});

const myHighlightStyle = HighlightStyle.define([
  { tag: tags.keyword, color: "#FF4500" }, // Red-orange keywords
  { tag: tags.string, color: "#FFFF66" }, // Light yellow strings
  { tag: tags.comment, color: "#66FF66", fontStyle: "italic" }, // Green comments
  { tag: tags.function(tags.variableName), color: "#66CCFF" }, // Light blue functions
  { tag: tags.number, color: "#FF66CC" }, // Pink numbers
  { tag: tags.variableName, color: "#FFFF33" }, // Brighter yellow variable names
  { tag: tags.operator, color: "#FF66FF" }, // Magenta operators
  { tag: tags.meta, color: "#66FFFF" }, // Cyan meta
  { tag: tags.attributeName, color: "#FFD700" }, // Gold attribute names
  { tag: tags.className, color: "#FF6600" }, // Orange class names
  { tag: tags.typeName, color: "#66FFCC" }, // Mint green type names
  { tag: tags.tagName, color: "#FF4500" }, // Red-orange tag names
  { tag: tags.bracket, color: "#FFFF66" }, // Light yellow brackets
  { tag: tags.angleBracket, color: "#FFCC66" }, // Peach angle brackets
  { tag: tags.link, color: "#66CCFF" }, // Light blue links
  { tag: tags.heading, color: "#FFCC00", fontWeight: "bold" }, // Dark yellow headings
  { tag: tags.emphasis, color: "#FFFF33", fontStyle: "italic" }, // Brighter yellow italic
  { tag: tags.strong, color: "#FFFF33", fontWeight: "bold" }, // Brighter yellow bold
  { tag: tags.strikethrough, color: "#FFFF33", textDecoration: "line-through" }, // Brighter yellow strikethrough
  { tag: tags.attributeValue, color: "#FFD700" }, // Gold attribute values
  { tag: tags.definition(tags.typeName), color: "#FFD700" }, // Gold type definitions
  { tag: tags.definition(tags.className), color: "#FF6600" }, // Orange class definitions
]);

console.log(myHighlightStyle)

export class CodeEdit extends HTMLElement {
  constructor() {
    super()
    this.attachShadow({mode: 'open'})
  }

  connectedCallback() {
    this.shadowRoot.adoptedStyleSheets = [this.constructor.styleSheet]
    this.initEditor()
  }

  static css = `
    :host {
      display: flex;
      flex-direction: column;
      align-items: stretch;
      flex-grow: 1;
      background-color: #fff;
      height: 100%;
    }
  `

  static get styleSheet() {
    if (this._styleSheet === undefined) {
      this._styleSheet = new CSSStyleSheet()
      this._styleSheet.replaceSync(this.css)
    }
    return this._styleSheet
  }

  set value(value) {
    if (this.view) {
      this.view.dispatch({changes: {
        from: 0,
        to: this.view.state.doc.length,
        insert: value
      }})
    } else {
      this._value = value
    }
  }

  get value() {
    if (this.view) {
      return this.view.state.doc.toString()
    } else {
      return this._value ?? ''
    }
  }

  set fileType(value) {
    this._fileType = value
    if (this.view) {
      const langPlugins = this.langPlugins
      this.view.dispatch({
        effects: 
        this.languageCompartment.reconfigure(langPlugins)
      })
    }
  }

  get fileType() {
    return this._fileType
  }

  get langPlugins() {
    const cmView = window.CodeMirrorModules['@codemirror/view']
    const cmState = window.CodeMirrorModules['@codemirror/state']
    const cmLanguage = window.CodeMirrorModules['@codemirror/language']
    const cmJavaScript = window.CodeMirrorModules['@codemirror/lang-javascript']
    const cmCss = window.CodeMirrorModules['@codemirror/lang-css']
    const cmHtml = window.CodeMirrorModules['@codemirror/lang-html']
    const cmJson = window.CodeMirrorModules['@codemirror/lang-json']
    const cmMarkdown = window.CodeMirrorModules['@codemirror/lang-markdown']
    const langPlugins = []
    if (['js', 'javascript'].includes(this.fileType)) {
      langPlugins.push(cmJavaScript.javascriptLanguage)
    } else if (this.fileType === 'css') {
      langPlugins.push(cmCss.cssLanguage)
    } else if (this.fileType === 'html') {
      langPlugins.push(cmHtml.htmlLanguage)
    } else if (this.fileType === 'json') {
      langPlugins.push(cmJson.jsonLanguage)
    } else if (this.fileType === 'md') {
      const codeLanguages = [
        cmLanguage.LanguageDescription.of({
          name: 'javascript',
          alias: ['js'],
          async load() {
            return new cmLanguage.LanguageSupport(cmJavaScript.javascriptLanguage)
          },
        }),
        cmLanguage.LanguageDescription.of({
          name: 'css',
          async load() {
            return new cmLanguage.LanguageSupport(cmCss.cssLanguage)
          },
        }),
        cmLanguage.LanguageDescription.of({
          name: 'json',
          async load() {
            return new cmLanguage.LanguageSupport(cmJson.jsonLanguage)
          },
        }),
        cmLanguage.LanguageDescription.of({
          name: 'html',
          async load() {
            const javascript = new cmLanguage.LanguageSupport(cmJavaScript.javascriptLanguage)
            const css = new cmLanguage.LanguageSupport(cmCss.cssLanguage)
            return new cmLanguage.LanguageSupport(cmHtml.htmlLanguage, [css, javascript])
          },
        }),
      ]
      const { language, support } = cmMarkdown.markdown({codeLanguages, addKeymap: false})
      const markdownSupport = new cmLanguage.LanguageSupport(
        language, [...support, cmState.Prec.high(cmView.keymap.of(cmMarkdown.markdownKeymap))]
      )
      langPlugins.push(
        markdownSupport
      )
    }
    return langPlugins
  }

  initEditor() {
    const cmView = window.CodeMirrorModules['@codemirror/view']
    const cmState = window.CodeMirrorModules['@codemirror/state']
    const cmLanguage = window.CodeMirrorModules['@codemirror/language']
    const cmCommands = window.CodeMirrorModules['@codemirror/commands']
    const cmAutocomplete = window.CodeMirrorModules['@codemirror/autocomplete']
    const cmSearch = window.CodeMirrorModules['@codemirror/search']
    const cmLint = window.CodeMirrorModules['@codemirror/lint']
    this.languageCompartment = new cmState.Compartment()
    const langPlugins = this.langPlugins
    const basicSetup = [
      cmView.lineNumbers(),
      cmView.highlightActiveLineGutter(),
      cmView.highlightSpecialChars(),
      cmCommands.history(),
      cmLanguage.foldGutter(),
      cmView.drawSelection(),
      cmView.dropCursor(),
      cmState.EditorState.allowMultipleSelections.of(true),
      cmLanguage.indentOnInput(),
      cmLanguage.bracketMatching(),
      cmAutocomplete.closeBrackets(),
      cmAutocomplete.autocompletion(),
      cmView.rectangularSelection(),
      cmView.crosshairCursor(),
      cmView.highlightActiveLine(),
      cmSearch.highlightSelectionMatches(),
      cmLanguage.syntaxHighlighting(myHighlightStyle),
      cmView.keymap.of([
        ...cmAutocomplete.closeBracketsKeymap,
        ...cmCommands.defaultKeymap,
        ...cmSearch.searchKeymap,
        ...cmCommands.historyKeymap,
        ...cmLanguage.foldKeymap,
        ...cmAutocomplete.completionKeymap,
        ...cmLint.lintKeymap,
      ]),
    ]
    const viewTheme = cmView.EditorView.theme({
      '&': {flexGrow: '1', height: '100%'},
      '.cm-scroller': {overflow: 'auto'}
    })
    this.view = new cmView.EditorView({
      doc: this._value ?? '',
      extensions: [
        ...basicSetup,
        this.languageCompartment.of(langPlugins),
        myTheme,
        cmView.EditorView.updateListener.of(e => {
          if (e.docChanged) {
            this.dispatchEvent(new CustomEvent(
              'code-input', {bubbles: true, composed: true}
            ))
          }
        }),
      ],
      root: this.shadowRoot,
    })
    this.shadowRoot.append(this.view.dom)
  }

  focus() {
    this.view.focus()
  }
}

app-view.js

export class AppView extends HTMLElement {
  constructor() {
    super()
    this.attachShadow({mode: 'open'})
  }

  connectedCallback() {
    const globalStyle = document.createElement('style')
    globalStyle.textContent = `
      body {
        margin: 0;
        padding: 0;
      }
      html {
        box-sizing: border-box;
      }
      *, *:before, *:after {
        box-sizing: inherit;
      }
    `
    document.head.append(globalStyle)

    const style = document.createElement('style')
    style.textContent = `
    `
    this.shadowRoot.append(style)

    const codeEdit = document.createElement('code-edit')
    codeEdit.fileType = 'js'
    codeEdit.value = `const x = 9`
    this.shadowRoot.append(codeEdit)
  }
}

app.js

import {CodeEdit} from '/code-edit.js'
import {AppView} from '/app-view.js'

customElements.define('code-edit', CodeEdit)
customElements.define('app-view', AppView)

async function setup() {
  const appView = document.createElement('app-view')
  document.body.append(appView)
}

await setup()