Add a dropdown to switch language in code blocks

Allow switching code language in code blocks in content editor
using a dropdown bubble menu.

Changelog: added

app/assets/javascripts/content_editor/components/code_block_bubble_menu.vue

+<script>
+import {
+  GlButton,
+  GlButtonGroup,
+  GlDropdown,
+  GlDropdownItem,
+  GlSearchBoxByType,
+  GlTooltipDirective as GlTooltip,
+} from '@gitlab/ui';
+import { BubbleMenu } from '@tiptap/vue-2';
+import codeBlockLanguageLoader from '../services/code_block_language_loader';
+import CodeBlockHighlight from '../extensions/code_block_highlight';
+import Diagram from '../extensions/diagram';
+import Frontmatter from '../extensions/frontmatter';
+import EditorStateObserver from './editor_state_observer.vue';
+
+const CODE_BLOCK_NODE_TYPES = [CodeBlockHighlight.name, Diagram.name, Frontmatter.name];
+
+export default {
+  components: {
+    BubbleMenu,
+    GlButton,
+    GlButtonGroup,
+    GlDropdown,
+    GlDropdownItem,
+    GlSearchBoxByType,
+    EditorStateObserver,
+  },
+  directives: {
+    GlTooltip,
+  },
+  inject: ['tiptapEditor'],
+  data() {
+    return {
+      selectedLanguage: {},
+      filterTerm: '',
+      filteredLanguages: [],
+    };
+  },
+  watch: {
+    filterTerm: {
+      handler(val) {
+        this.filteredLanguages = codeBlockLanguageLoader.filterLanguages(val);
+      },
+      immediate: true,
+    },
+  },
+  methods: {
+    shouldShow: ({ editor }) => {
+      return CODE_BLOCK_NODE_TYPES.some((type) => editor.isActive(type));
+    },
+
+    getSelectedLanguage() {
+      const { language } = this.tiptapEditor.getAttributes(this.getCodeBlockType());
+
+      this.selectedLanguage = codeBlockLanguageLoader.findLanguageBySyntax(language);
+    },
+
+    async setSelectedLanguage(language) {
+      this.selectedLanguage = language;
+
+      await codeBlockLanguageLoader.loadLanguages([language.syntax]);
+
+      this.tiptapEditor.commands.setCodeBlock({ language: this.selectedLanguage.syntax });
+    },
+
+    tippyOnBeforeUpdate(tippy, props) {
+      if (props.getReferenceClientRect) {
+        // eslint-disable-next-line no-param-reassign
+        props.getReferenceClientRect = () => {
+          const { view } = this.tiptapEditor;
+          const { from } = this.tiptapEditor.state.selection;
+
+          for (let { node } = view.domAtPos(from); node; node = node.parentElement) {
+            if (node.nodeName?.toLowerCase() === 'pre') {
+              return node.getBoundingClientRect();
+            }
+          }
+
+          return new DOMRect(-1000, -1000, 0, 0);
+        };
+      }
+    },
+
+    deleteCodeBlock() {
+      this.tiptapEditor.chain().focus().deleteNode(this.getCodeBlockType()).run();
+    },
+
+    getCodeBlockType() {
+      return (
+        CODE_BLOCK_NODE_TYPES.find((type) => this.tiptapEditor.isActive(type)) ||
+        CodeBlockHighlight.name
+      );
+    },
+  },
+};
+</script>
+<template>
+  <bubble-menu
+    data-testid="code-block-bubble-menu"
+    class="gl-shadow gl-rounded-base"
+    :editor="tiptapEditor"
+    plugin-key="bubbleMenuCodeBlock"
+    :should-show="shouldShow"
+    :tippy-options="{ onBeforeUpdate: tippyOnBeforeUpdate }"
+  >
+    <editor-state-observer @transaction="getSelectedLanguage">
+      <gl-button-group>
+        <gl-dropdown contenteditable="false" boundary="viewport" :text="selectedLanguage.label">
+          <template #header>
+            <gl-search-box-by-type
+              v-model="filterTerm"
+              :clear-button-title="__('Clear')"
+              :placeholder="__('Search')"
+            />
+          </template>
+
+          <template #highlighted-items>
+            <gl-dropdown-item :key="selectedLanguage.syntax" is-check-item :is-checked="true">
+              {{ selectedLanguage.label }}
+            </gl-dropdown-item>
+          </template>
+
+          <gl-dropdown-item
+            v-for="language in filteredLanguages"
+            v-show="selectedLanguage.syntax !== language.syntax"
+            :key="language.syntax"
+            @click="setSelectedLanguage(language)"
+          >
+            {{ language.label }}
+          </gl-dropdown-item>
+        </gl-dropdown>
+        <gl-button
+          v-gl-tooltip
+          variant="default"
+          category="primary"
+          size="medium"
+          :aria-label="__('Delete code block')"
+          :title="__('Delete code block')"
+          icon="remove"
+          @click="deleteCodeBlock"
+        />
+      </gl-button-group>
+    </editor-state-observer>
+  </bubble-menu>
+</template>

app/assets/javascripts/content_editor/components/content_editor.vue

@@ -5,6 +5,7 @@ import ContentEditorAlert from './content_editor_alert.vue';
 import ContentEditorProvider from './content_editor_provider.vue';
 import EditorStateObserver from './editor_state_observer.vue';
 import FormattingBubbleMenu from './formatting_bubble_menu.vue';
+import CodeBlockBubbleMenu from './code_block_bubble_menu.vue';
 import TopToolbar from './top_toolbar.vue';
 import LoadingIndicator from './loading_indicator.vue';
 
@@ -16,6 +17,7 @@ export default {
     TiptapEditorContent,
     TopToolbar,
     FormattingBubbleMenu,
+    CodeBlockBubbleMenu,
     EditorStateObserver,
   },
   props: {
@@ -89,6 +91,7 @@ export default {
         <top-toolbar ref="toolbar" class="gl-mb-4" />
         <div class="gl-relative">
           <formatting-bubble-menu />
+          <code-block-bubble-menu />
           <tiptap-editor-content class="md" :editor="contentEditor.tiptapEditor" />
           <loading-indicator />
         </div>

app/assets/javascripts/content_editor/components/formatting_bubble_menu.vue

@@ -3,6 +3,10 @@ import { GlButtonGroup } from '@gitlab/ui';
 import { BubbleMenu } from '@tiptap/vue-2';
 import { BUBBLE_MENU_TRACKING_ACTION } from '../constants';
 import trackUIControl from '../services/track_ui_control';
+import Code from '../extensions/code';
+import CodeBlockHighlight from '../extensions/code_block_highlight';
+import Diagram from '../extensions/diagram';
+import Frontmatter from '../extensions/frontmatter';
 import ToolbarButton from './toolbar_button.vue';
 
 export default {
@@ -16,6 +20,14 @@ export default {
     trackToolbarControlExecution({ contentType, value }) {
       trackUIControl({ action: BUBBLE_MENU_TRACKING_ACTION, property: contentType, value });
     },
+
+    shouldShow: ({ editor, from, to }) => {
+      if (from === to) return false;
+
+      const exclude = [Code.name, CodeBlockHighlight.name, Diagram.name, Frontmatter.name];
+
+      return !exclude.some((type) => editor.isActive(type));
+    },
   },
 };
 </script>
@@ -24,6 +36,7 @@ export default {
     data-testid="formatting-bubble-menu"
     class="gl-shadow gl-rounded-base"
     :editor="tiptapEditor"
+    :should-show="shouldShow"
   >
     <gl-button-group>
       <toolbar-button

app/assets/javascripts/content_editor/extensions/code_block_highlight.js

 import { CodeBlockLowlight } from '@tiptap/extension-code-block-lowlight';
 import { textblockTypeInputRule } from '@tiptap/core';
-import { isFunction } from 'lodash';
+import codeBlockLanguageLoader from '../services/code_block_language_loader';
 
 const extractLanguage = (element) => element.getAttribute('lang');
-const backtickInputRegex = /^```([a-z]+)?[\s\n]$/;
-const tildeInputRegex = /^~~~([a-z]+)?[\s\n]$/;
-
-const loadLanguageFromInputRule = (languageLoader) => (match) => {
-  const language = match[1];
-
-  if (isFunction(languageLoader?.loadLanguages)) {
-    languageLoader.loadLanguages([language]);
-  }
-
-  return {
-    language,
-  };
-};
+export const backtickInputRegex = /^```([a-z]+)?[\s\n]$/;
+export const tildeInputRegex = /^~~~([a-z]+)?[\s\n]$/;
 
 export default CodeBlockLowlight.extend({
   isolating: true,
+  exitOnArrowDown: false,
 
   addOptions() {
     return {
       ...this.parent?.(),
-      languageLoader: {},
+      languageLoader: codeBlockLanguageLoader,
     };
   },
 
@@ -42,26 +31,36 @@ export default CodeBlockLowlight.extend({
   },
   addInputRules() {
     const { languageLoader } = this.options;
+    const getAttributes = (match) => languageLoader?.loadLanguageFromInputRule(match) || {};
 
     return [
       textblockTypeInputRule({
         find: backtickInputRegex,
         type: this.type,
-        getAttributes: loadLanguageFromInputRule(languageLoader),
+        getAttributes,
       }),
       textblockTypeInputRule({
         find: tildeInputRegex,
         type: this.type,
-        getAttributes: loadLanguageFromInputRule(languageLoader),
+        getAttributes,
       }),
     ];
   },
+  parseHTML() {
+    return [
+      ...(this.parent?.() || []),
+      {
+        tag: 'div.markdown-code-block',
+        skip: true,
+      },
+    ];
+  },
   renderHTML({ HTMLAttributes }) {
     return [
       'pre',
       {
         ...HTMLAttributes,
-        class: `content-editor-code-block ${HTMLAttributes.class}`,
+        class: `content-editor-code-block ${gon.user_color_scheme} ${HTMLAttributes.class}`,
       },
       ['code', {}, 0],
     ];

app/assets/javascripts/content_editor/services/code_block_language_loader.js

-export default class CodeBlockLanguageLoader {
-  constructor(lowlight) {
-    this.lowlight = lowlight;
-  }
+import { lowlight } from 'lowlight/lib/core';
+import { __, sprintf } from '~/locale';
+
+/* eslint-disable @gitlab/require-i18n-strings */
+// List of languages referenced from https://github.com/wooorm/lowlight#data
+const CODE_BLOCK_LANGUAGES = [
+  { syntax: '1c', label: '1C:Enterprise' },
+  { syntax: 'abnf', label: 'Augmented Backus-Naur Form' },
+  { syntax: 'accesslog', label: 'Apache Access Log' },
+  { syntax: 'actionscript', variants: 'as', label: 'ActionScript' },
+  { syntax: 'ada', label: 'Ada' },
+  { syntax: 'angelscript', variants: 'asc', label: 'AngelScript' },
+  { syntax: 'apache', variants: 'apacheconf', label: 'Apache config' },
+  { syntax: 'applescript', variants: 'osascript', label: 'AppleScript' },
+  { syntax: 'arcade', label: 'ArcGIS Arcade' },
+  { syntax: 'arduino', variants: 'ino', label: 'Arduino' },
+  { syntax: 'armasm', variants: 'arm', label: 'ARM Assembly' },
+  { syntax: 'asciidoc', variants: 'adoc', label: 'AsciiDoc' },
+  { syntax: 'aspectj', label: 'AspectJ' },
+  { syntax: 'autohotkey', variants: 'ahk', label: 'AutoHotkey' },
+  { syntax: 'autoit', label: 'AutoIt' },
+  { syntax: 'avrasm', label: 'AVR Assembly' },
+  { syntax: 'awk', label: 'Awk' },
+  { syntax: 'axapta', variants: 'x++', label: 'X++' },
+  { syntax: 'bash', variants: 'sh', label: 'Bash' },
+  { syntax: 'basic', label: 'BASIC' },
+  { syntax: 'bnf', label: 'Backus-Naur Form' },
+  { syntax: 'brainfuck', variants: 'bf', label: 'Brainfuck' },
+  { syntax: 'c', variants: 'h', label: 'C' },
+  { syntax: 'cal', label: 'C/AL' },
+  { syntax: 'capnproto', variants: 'capnp', label: "Cap'n Proto" },
+  { syntax: 'ceylon', label: 'Ceylon' },
+  { syntax: 'clean', variants: 'icl, dcl', label: 'Clean' },
+  { syntax: 'clojure', variants: 'clj, edn', label: 'Clojure' },
+  { syntax: 'clojure-repl', label: 'Clojure REPL' },
+  { syntax: 'cmake', variants: 'cmake.in', label: 'CMake' },
+  { syntax: 'coffeescript', variants: 'coffee, cson, iced', label: 'CoffeeScript' },
+  { syntax: 'coq', label: 'Coq' },
+  { syntax: 'cos', variants: 'cls', label: 'Caché Object Script' },
+  { syntax: 'cpp', variants: 'cc, c++, h++, hpp, hh, hxx, cxx', label: 'C++' },
+  { syntax: 'crmsh', variants: 'crm, pcmk', label: 'crmsh' },
+  { syntax: 'crystal', variants: 'cr', label: 'Crystal' },
+  { syntax: 'csharp', variants: 'cs, c#', label: 'C#' },
+  { syntax: 'csp', label: 'CSP' },
+  { syntax: 'css', label: 'CSS' },
+  { syntax: 'd', label: 'D' },
+  { syntax: 'dart', label: 'Dart' },
+  { syntax: 'delphi', variants: 'dpr, dfm, pas, pascal', label: 'Delphi' },
+  { syntax: 'diff', variants: 'patch', label: 'Diff' },
+  { syntax: 'django', variants: 'jinja', label: 'Django' },
+  { syntax: 'dns', variants: 'bind, zone', label: 'DNS Zone' },
+  { syntax: 'dockerfile', variants: 'docker', label: 'Dockerfile' },
+  { syntax: 'dos', variants: 'bat, cmd', label: 'Batch file (DOS)' },
+  { syntax: 'dsconfig', label: 'DSConfig' },
+  { syntax: 'dts', label: 'Device Tree' },
+  { syntax: 'dust', variants: 'dst', label: 'Dust' },
+  { syntax: 'ebnf', label: 'Extended Backus-Naur Form' },
+  { syntax: 'elixir', variants: 'ex, exs', label: 'Elixir' },
+  { syntax: 'elm', label: 'Elm' },
+  { syntax: 'erb', label: 'ERB' },
+  { syntax: 'erlang', variants: 'erl', label: 'Erlang' },
+  { syntax: 'erlang-repl', label: 'Erlang REPL' },
+  { syntax: 'excel', variants: 'xlsx, xls', label: 'Excel formulae' },
+  { syntax: 'fix', label: 'FIX' },
+  { syntax: 'flix', label: 'Flix' },
+  { syntax: 'fortran', variants: 'f90, f95', label: 'Fortran' },
+  { syntax: 'fsharp', variants: 'fs, f#', label: 'F#' },
+  { syntax: 'gams', variants: 'gms', label: 'GAMS' },
+  { syntax: 'gauss', variants: 'gss', label: 'GAUSS' },
+  { syntax: 'gcode', variants: 'nc', label: 'G-code (ISO 6983)' },
+  { syntax: 'gherkin', variants: 'feature', label: 'Gherkin' },
+  { syntax: 'glsl', label: 'GLSL' },
+  { syntax: 'gml', label: 'GML' },
+  { syntax: 'go', variants: 'golang', label: 'Go' },
+  { syntax: 'golo', label: 'Golo' },
+  { syntax: 'gradle', label: 'Gradle' },
+  { syntax: 'graphql', variants: 'gql', label: 'GraphQL' },
+  { syntax: 'groovy', label: 'Groovy' },
+  { syntax: 'haml', label: 'HAML' },
+  {
+    syntax: 'handlebars',
+    variants: 'hbs, html.hbs, html.handlebars, htmlbars',
+    label: 'Handlebars',
+  },
+  { syntax: 'haskell', variants: 'hs', label: 'Haskell' },
+  { syntax: 'haxe', variants: 'hx', label: 'Haxe' },
+  { syntax: 'hsp', label: 'HSP' },
+  { syntax: 'http', variants: 'https', label: 'HTTP' },
+  { syntax: 'hy', variants: 'hylang', label: 'Hy' },
+  { syntax: 'inform7', variants: 'i7', label: 'Inform 7' },
+  { syntax: 'ini', variants: 'toml', label: 'TOML, also INI' },
+  { syntax: 'irpf90', label: 'IRPF90' },
+  { syntax: 'isbl', label: 'ISBL' },
+  { syntax: 'java', variants: 'jsp', label: 'Java' },
+  { syntax: 'javascript', variants: 'js, jsx, mjs, cjs', label: 'Javascript' },
+  { syntax: 'jboss-cli', variants: 'wildfly-cli', label: 'JBoss CLI' },
+  { syntax: 'json', label: 'JSON' },
+  { syntax: 'julia', label: 'Julia' },
+  { syntax: 'julia-repl', variants: 'jldoctest', label: 'Julia REPL' },
+  { syntax: 'kotlin', variants: 'kt, kts', label: 'Kotlin' },
+  { syntax: 'lasso', variants: 'ls, lassoscript', label: 'Lasso' },
+  { syntax: 'latex', variants: 'tex', label: 'LaTeX' },
+  { syntax: 'ldif', label: 'LDIF' },
+  { syntax: 'leaf', label: 'Leaf' },
+  { syntax: 'less', label: 'Less' },
+  { syntax: 'lisp', label: 'Lisp' },
+  { syntax: 'livecodeserver', label: 'LiveCode' },
+  { syntax: 'livescript', variants: 'ls', label: 'LiveScript' },
+  { syntax: 'llvm', label: 'LLVM IR' },
+  { syntax: 'lsl', label: 'LSL (Linden Scripting Language)' },
+  { syntax: 'lua', label: 'Lua' },
+  { syntax: 'makefile', variants: 'mk, mak, make', label: 'Makefile' },
+  { syntax: 'markdown', variants: 'md, mkdown, mkd', label: 'Markdown' },
+  { syntax: 'mathematica', variants: 'mma, wl', label: 'Mathematica' },
+  { syntax: 'matlab', label: 'Matlab' },
+  { syntax: 'maxima', label: 'Maxima' },
+  { syntax: 'mel', label: 'MEL' },
+  { syntax: 'mercury', variants: 'm, moo', label: 'Mercury' },
+  { syntax: 'mipsasm', variants: 'mips', label: 'MIPS Assembly' },
+  { syntax: 'mizar', label: 'Mizar' },
+  { syntax: 'mojolicious', label: 'Mojolicious' },
+  { syntax: 'monkey', label: 'Monkey' },
+  { syntax: 'moonscript', variants: 'moon', label: 'MoonScript' },
+  { syntax: 'n1ql', label: 'N1QL' },
+  { syntax: 'nestedtext', variants: 'nt', label: 'Nested Text' },
+  { syntax: 'nginx', variants: 'nginxconf', label: 'Nginx config' },
+  { syntax: 'nim', label: 'Nim' },
+  { syntax: 'nix', variants: 'nixos', label: 'Nix' },
+  { syntax: 'node-repl', label: 'Node REPL' },
+  { syntax: 'nsis', label: 'NSIS' },
+  {
+    syntax: 'objectivec',
+    variants: 'mm, objc, obj-c, obj-c++, objective-c++',
+    label: 'Objective-C',
+  },
+  { syntax: 'ocaml', variants: 'ml', label: 'OCaml' },
+  { syntax: 'openscad', variants: 'scad', label: 'OpenSCAD' },
+  { syntax: 'oxygene', label: 'Oxygene' },
+  { syntax: 'parser3', label: 'Parser3' },
+  { syntax: 'perl', variants: 'pl, pm', label: 'Perl' },
+  { syntax: 'pf', variants: 'pf.conf', label: 'Packet Filter config' },
+  { syntax: 'pgsql', variants: 'postgres, postgresql', label: 'PostgreSQL' },
+  { syntax: 'php', label: 'PHP' },
+  { syntax: 'php-template', label: 'PHP template' },
+  { syntax: 'plaintext', variants: 'text, txt', label: 'Plain text' },
+  { syntax: 'pony', label: 'Pony' },
+  { syntax: 'powershell', variants: 'pwsh, ps, ps1', label: 'PowerShell' },
+  { syntax: 'processing', variants: 'pde', label: 'Processing' },
+  { syntax: 'profile', label: 'Python profiler' },
+  { syntax: 'prolog', label: 'Prolog' },
+  { syntax: 'properties', label: '.properties' },
+  { syntax: 'protobuf', label: 'Protocol Buffers' },
+  { syntax: 'puppet', variants: 'pp', label: 'Puppet' },
+  { syntax: 'purebasic', variants: 'pb, pbi', label: 'PureBASIC' },
+  { syntax: 'python', variants: 'py, gyp, ipython', label: 'Python' },
+  { syntax: 'python-repl', variants: 'pycon', label: 'Python REPL' },
+  { syntax: 'q', variants: 'k, kdb', label: 'Q' },
+  { syntax: 'qml', variants: 'qt', label: 'QML' },
+  { syntax: 'r', label: 'R' },
+  { syntax: 'reasonml', variants: 're', label: 'ReasonML' },
+  { syntax: 'rib', label: 'RenderMan RIB' },
+  { syntax: 'roboconf', variants: 'graph, instances', label: 'Roboconf' },
+  { syntax: 'routeros', variants: 'mikrotik', label: 'Microtik RouterOS script' },
+  { syntax: 'rsl', label: 'RenderMan RSL' },
+  { syntax: 'ruby', variants: 'rb, gemspec, podspec, thor, irb', label: 'Ruby' },
+  { syntax: 'ruleslanguage', label: 'Oracle Rules Language' },
+  { syntax: 'rust', variants: 'rs', label: 'Rust' },
+  { syntax: 'sas', label: 'SAS' },
+  { syntax: 'scala', label: 'Scala' },
+  { syntax: 'scheme', label: 'Scheme' },
+  { syntax: 'scilab', variants: 'sci', label: 'Scilab' },
+  { syntax: 'scss', label: 'SCSS' },
+  { syntax: 'shell', variants: 'console, shellsession', label: 'Shell Session' },
+  { syntax: 'smali', label: 'Smali' },
+  { syntax: 'smalltalk', variants: 'st', label: 'Smalltalk' },
+  { syntax: 'sml', variants: 'ml', label: 'SML (Standard ML)' },
+  { syntax: 'sqf', label: 'SQF' },
+  { syntax: 'sql', label: 'SQL' },
+  { syntax: 'stan', variants: 'stanfuncs', label: 'Stan' },
+  { syntax: 'stata', variants: 'do, ado', label: 'Stata' },
+  { syntax: 'step21', variants: 'p21, step, stp', label: 'STEP Part 21' },
+  { syntax: 'stylus', variants: 'styl', label: 'Stylus' },
+  { syntax: 'subunit', label: 'SubUnit' },
+  { syntax: 'swift', label: 'Swift' },
+  { syntax: 'taggerscript', label: 'Tagger Script' },
+  { syntax: 'tap', label: 'Test Anything Protocol' },
+  { syntax: 'tcl', variants: 'tk', label: 'Tcl' },
+  { syntax: 'thrift', label: 'Thrift' },
+  { syntax: 'tp', label: 'TP' },
+  { syntax: 'twig', variants: 'craftcms', label: 'Twig' },
+  { syntax: 'typescript', variants: 'ts, tsx', label: 'TypeScript' },
+  { syntax: 'vala', label: 'Vala' },
+  { syntax: 'vbnet', variants: 'vb', label: 'Visual Basic .NET' },
+  { syntax: 'vbscript', variants: 'vbs', label: 'VBScript' },
+  { syntax: 'vbscript-html', label: 'VBScript in HTML' },
+  { syntax: 'verilog', variants: 'v, sv, svh', label: 'Verilog' },
+  { syntax: 'vhdl', label: 'VHDL' },
+  { syntax: 'vim', label: 'Vim Script' },
+  { syntax: 'wasm', label: 'WebAssembly' },
+  { syntax: 'wren', label: 'Wren' },
+  { syntax: 'x86asm', label: 'Intel x86 Assembly' },
+  { syntax: 'xl', variants: 'tao', label: 'XL' },
+  {
+    syntax: 'xml',
+    variants: 'html, xhtml, rss, atom, xjb, xsd, xsl, plist, wsf, svg',
+    label: 'HTML, XML',
+  },
+  { syntax: 'xquery', variants: 'xpath, xq', label: 'XQuery' },
+  { syntax: 'yaml', variants: 'yml', label: 'YAML' },
+  { syntax: 'zephir', variants: 'zep', label: 'Zephir' },
+];
+/* eslint-enable @gitlab/require-i18n-strings */
+
+const codeBlockLanguageLoader = {
+  lowlight,
+
+  allLanguages: CODE_BLOCK_LANGUAGES,
+
+  findLanguageBySyntax(value) {
+    const lowercaseValue = value?.toLowerCase() || 'plaintext';
+    return (
+      this.allLanguages.find(
+        ({ syntax, variants }) =>
+          syntax === lowercaseValue || variants?.toLowerCase().split(', ').includes(lowercaseValue),
+      ) || {
+        syntax: lowercaseValue,
+        label: sprintf(__(`Custom (%{language})`), { language: lowercaseValue }),
+      }
+    );
+  },
+
+  filterLanguages(value) {
+    if (!value) return this.allLanguages;
+
+    const lowercaseValue = value?.toLowerCase() || '';
+    return this.allLanguages.filter(
+      ({ syntax, label, variants }) =>
+        syntax.toLowerCase().includes(lowercaseValue) ||
+        label.toLowerCase().includes(lowercaseValue) ||
+        variants?.toLowerCase().includes(lowercaseValue),
+    );
+  },
 
   isLanguageLoaded(language) {
     return this.lowlight.registered(language);
-  }
+  },
 
   loadLanguagesFromDOM(domTree) {
     const languages = [];
@@ -15,7 +253,15 @@ export default class CodeBlockLanguageLoader {
     });
 
     return this.loadLanguages(languages);
-  }
+  },
+
+  loadLanguageFromInputRule(match) {
+    const { syntax } = this.findLanguageBySyntax(match[1]);
+
+    this.loadLanguages([syntax]);
+
+    return { language: syntax };
+  },
 
   loadLanguages(languageList = []) {
     const loaders = languageList
@@ -31,5 +277,7 @@ export default class CodeBlockLanguageLoader {
       });
 
     return Promise.all(loaders);
-  }
-}
+  },
+};
+
+export default codeBlockLanguageLoader;

app/assets/javascripts/content_editor/services/create_content_editor.js

@@ -60,7 +60,7 @@ import { ContentEditor } from './content_editor';
 import createMarkdownSerializer from './markdown_serializer';
 import createMarkdownDeserializer from './markdown_deserializer';
 import trackInputRulesAndShortcuts from './track_input_rules_and_shortcuts';
-import CodeBlockLanguageLoader from './code_block_language_loader';
+import languageLoader from './code_block_language_loader';
 
 const createTiptapEditor = ({ extensions = [], ...options } = {}) =>
   new Editor({
@@ -86,7 +86,6 @@ export const createContentEditor = ({
 
   const eventHub = eventHubFactory();
 
-  const languageLoader = new CodeBlockLanguageLoader(lowlight);
   const builtInContentEditorExtensions = [
     Attachment.configure({ uploadsPath, renderMarkdown, eventHub }),
     Audio,

app/assets/javascripts/content_editor/services/track_input_rules_and_shortcuts.js

@@ -8,12 +8,12 @@ import {
   INPUT_RULE_TRACKING_ACTION,
 } from '../constants';
 
-const trackKeyboardShortcut = (contentType, commandFn, shortcut) => () => {
+const trackKeyboardShortcut = (contentType, commandFn, shortcut) => (...args) => {
   Tracking.event(undefined, KEYBOARD_SHORTCUT_TRACKING_ACTION, {
     label: CONTENT_EDITOR_TRACKING_LABEL,
     property: `${contentType}.${shortcut}`,
   });
-  return commandFn();
+  return commandFn(...args);
 };
 
 const trackInputRule = (contentType, inputRule) => {

locale/gitlab.pot

@@ -10969,6 +10969,9 @@ msgstr ""
 msgid "CurrentUser|Start an Ultimate trial"
 msgstr ""
 
+msgid "Custom (%{language})"
+msgstr ""
+
 msgid "Custom Attributes"
 msgstr ""
 
@@ -11965,6 +11968,9 @@ msgstr ""
 msgid "Delete badge"
 msgstr ""
 
+msgid "Delete code block"
+msgstr ""
+
 msgid "Delete column"
 msgstr ""
 

spec/frontend/content_editor/components/code_block_bubble_menu_spec.js

+import { BubbleMenu } from '@tiptap/vue-2';
+import { GlButton, GlDropdown, GlDropdownItem, GlSearchBoxByType } from '@gitlab/ui';
+import Vue from 'vue';
+import { mountExtended } from 'helpers/vue_test_utils_helper';
+import CodeBlockBubbleMenu from '~/content_editor/components/code_block_bubble_menu.vue';
+import eventHubFactory from '~/helpers/event_hub_factory';
+import CodeBlockHighlight from '~/content_editor/extensions/code_block_highlight';
+import codeBlockLanguageLoader from '~/content_editor/services/code_block_language_loader';
+import { createTestEditor, emitEditorEvent } from '../test_utils';
+
+describe('content_editor/components/code_block_bubble_menu', () => {
+  let wrapper;
+  let tiptapEditor;
+  let bubbleMenu;
+  let eventHub;
+
+  const buildEditor = () => {
+    tiptapEditor = createTestEditor({ extensions: [CodeBlockHighlight] });
+    eventHub = eventHubFactory();
+  };
+
+  const buildWrapper = () => {
+    wrapper = mountExtended(CodeBlockBubbleMenu, {
+      provide: {
+        tiptapEditor,
+        eventHub,
+      },
+    });
+  };
+
+  const findDropdownItems = () => wrapper.findAllComponents(GlDropdownItem);
+  const findDropdownItemsData = () =>
+    findDropdownItems().wrappers.map((x) => ({
+      text: x.text(),
+      visible: x.isVisible(),
+      checked: x.props('isChecked'),
+    }));
+
+  beforeEach(() => {
+    buildEditor();
+    buildWrapper();
+  });
+
+  afterEach(() => {
+    wrapper.destroy();
+  });
+
+  it('renders bubble menu component', async () => {
+    tiptapEditor.commands.insertContent('<pre>test</pre>');
+    bubbleMenu = wrapper.findComponent(BubbleMenu);
+
+    await emitEditorEvent({ event: 'transaction', tiptapEditor });
+
+    expect(bubbleMenu.props('editor')).toBe(tiptapEditor);
+    expect(bubbleMenu.classes()).toEqual(['gl-shadow', 'gl-rounded-base']);
+  });
+
+  it('selects plaintext language by default', async () => {
+    tiptapEditor.commands.insertContent('<pre>test</pre>');
+    bubbleMenu = wrapper.findComponent(BubbleMenu);
+
+    await emitEditorEvent({ event: 'transaction', tiptapEditor });
+
+    expect(wrapper.findComponent(GlDropdown).props('text')).toBe('Plain text');
+  });
+
+  it('selects appropriate language based on the code block', async () => {
+    tiptapEditor.commands.insertContent('<pre lang="javascript">var a = 2;</pre>');
+    bubbleMenu = wrapper.findComponent(BubbleMenu);
+
+    await emitEditorEvent({ event: 'transaction', tiptapEditor });
+
+    expect(wrapper.findComponent(GlDropdown).props('text')).toBe('Javascript');
+  });
+
+  it("selects Custom (syntax) if the language doesn't exist in the list", async () => {
+    tiptapEditor.commands.insertContent('<pre lang="nomnoml">test</pre>');
+    bubbleMenu = wrapper.findComponent(BubbleMenu);
+
+    await emitEditorEvent({ event: 'transaction', tiptapEditor });
+
+    expect(wrapper.findComponent(GlDropdown).props('text')).toBe('Custom (nomnoml)');
+  });
+
+  it('delete button deletes the code block', async () => {
+    tiptapEditor.commands.insertContent('<pre lang="javascript">var a = 2;</pre>');
+
+    await wrapper.findComponent(GlButton).vm.$emit('click');
+
+    expect(tiptapEditor.getText()).toBe('');
+  });
+
+  describe('when opened and search is changed', () => {
+    beforeEach(async () => {
+      tiptapEditor.commands.insertContent('<pre lang="javascript">var a = 2;</pre>');
+
+      wrapper.findComponent(GlSearchBoxByType).vm.$emit('input', 'js');
+
+      await Vue.nextTick();
+    });
+
+    it('shows dropdown items', () => {
+      expect(findDropdownItemsData()).toEqual([
+        { text: 'Javascript', visible: true, checked: true },
+        { text: 'Java', visible: true, checked: false },
+        { text: 'Javascript', visible: false, checked: false },
+        { text: 'JSON', visible: true, checked: false },
+      ]);
+    });
+
+    describe('when dropdown item is clicked', () => {
+      beforeEach(async () => {
+        jest.spyOn(codeBlockLanguageLoader, 'loadLanguages').mockResolvedValue();
+
+        findDropdownItems().at(1).vm.$emit('click');
+
+        await Vue.nextTick();
+      });
+
+      it('loads language', () => {
+        expect(codeBlockLanguageLoader.loadLanguages).toHaveBeenCalledWith(['java']);
+      });
+
+      it('sets code block', () => {
+        expect(tiptapEditor.getJSON()).toMatchObject({
+          content: [
+            {
+              type: 'codeBlock',
+              attrs: {
+                language: 'java',
+              },
+            },
+          ],
+        });
+      });
+
+      it('updates selected dropdown', () => {
+        expect(wrapper.findComponent(GlDropdown).props('text')).toBe('Java');
+      });
+    });
+  });
+});

spec/frontend/content_editor/components/formatting_bubble_menu_spec.js

@@ -9,7 +9,7 @@ import {
 } from '~/content_editor/constants';
 import { createTestEditor } from '../test_utils';
 
-describe('content_editor/components/top_toolbar', () => {
+describe('content_editor/components/formatting_bubble_menu', () => {
   let wrapper;
   let trackingSpy;
   let tiptapEditor;

spec/frontend/content_editor/extensions/frontmatter_spec.js

@@ -23,7 +23,7 @@ describe('content_editor/extensions/frontmatter', () => {
   });
 
   it('does not insert a frontmatter block when executing code block input rule', () => {
-    const expectedDoc = doc(codeBlock(''));
+    const expectedDoc = doc(codeBlock({ language: 'plaintext' }, ''));
     const inputRuleText = '``` ';
 
     triggerNodeInputRule({ tiptapEditor, inputRuleText });

spec/frontend/content_editor/services/code_block_language_loader_spec.js

-import CodeBlockLanguageBlocker from '~/content_editor/services/code_block_language_loader';
+import codeBlockLanguageBlocker from '~/content_editor/services/code_block_language_loader';
+import waitForPromises from 'helpers/wait_for_promises';
+import { backtickInputRegex } from '~/content_editor/extensions/code_block_highlight';
 
 describe('content_editor/services/code_block_language_loader', () => {
   let languageLoader;
@@ -12,7 +14,43 @@ describe('content_editor/services/code_block_language_loader', () => {
         .mockImplementation((language) => lowlight.languages.push(language)),
       registered: jest.fn().mockImplementation((language) => lowlight.languages.includes(language)),
     };
-    languageLoader = new CodeBlockLanguageBlocker(lowlight);
+    languageLoader = codeBlockLanguageBlocker;
+    languageLoader.lowlight = lowlight;
+  });
+
+  describe('findLanguageBySyntax', () => {
+    it.each`
+      syntax          | language
+      ${'javascript'} | ${{ syntax: 'javascript', label: 'Javascript' }}
+      ${'js'}         | ${{ syntax: 'javascript', label: 'Javascript' }}
+      ${'jsx'}        | ${{ syntax: 'javascript', label: 'Javascript' }}
+    `('returns a language by syntax and its variants', ({ syntax, language }) => {
+      expect(languageLoader.findLanguageBySyntax(syntax)).toMatchObject(language);
+    });
+
+    it('returns Custom (syntax) if the language does not exist', () => {
+      expect(languageLoader.findLanguageBySyntax('foobar')).toMatchObject({
+        syntax: 'foobar',
+        label: 'Custom (foobar)',
+      });
+    });
+
+    it('returns plaintext if no syntax is passed', () => {
+      expect(languageLoader.findLanguageBySyntax('')).toMatchObject({
+        syntax: 'plaintext',
+        label: 'Plain text',
+      });
+    });
+  });
+
+  describe('filterLanguages', () => {
+    it('filters languages by the given search term', () => {
+      expect(languageLoader.filterLanguages('ts')).toEqual([
+        { label: 'Device Tree', syntax: 'dts' },
+        { label: 'Kotlin', syntax: 'kotlin', variants: 'kt, kts' },
+        { label: 'TypeScript', syntax: 'typescript', variants: 'ts, tsx' },
+      ]);
+    });
   });
 
   describe('loadLanguages', () => {
@@ -56,6 +94,18 @@ describe('content_editor/services/code_block_language_loader', () => {
     });
   });
 
+  describe('loadLanguageFromInputRule', () => {
+    it('loads highlight.js language packages identified from the input rule', async () => {
+      const match = new RegExp(backtickInputRegex).exec('```js ');
+      const attrs = languageLoader.loadLanguageFromInputRule(match);
+
+      await waitForPromises();
+
+      expect(attrs).toEqual({ language: 'javascript' });
+      expect(lowlight.registerLanguage).toHaveBeenCalledWith('javascript', expect.any(Function));
+    });
+  });
+
   describe('isLanguageLoaded', () => {
     it('returns true when a language is registered', async () => {
       const language = 'javascript';

spec/support/shared_examples/features/content_editor_shared_examples.rb

 # frozen_string_literal: true
 
 RSpec.shared_examples 'edits content using the content editor' do
-  it 'formats text as bold using bubble menu' do
-    content_editor_testid = '[data-testid="content-editor"] [contenteditable]'
+  content_editor_testid = '[data-testid="content-editor"] [contenteditable].ProseMirror'
 
-    expect(page).to have_css(content_editor_testid)
+  describe 'formatting bubble menu' do
+    it 'shows a formatting bubble menu for a regular paragraph' do
+      expect(page).to have_css(content_editor_testid)
 
-    find(content_editor_testid).send_keys 'Typing text in the content editor'
-    find(content_editor_testid).send_keys [:shift, :left]
+      find(content_editor_testid).send_keys 'Typing text in the content editor'
+      find(content_editor_testid).send_keys [:shift, :left]
 
-    expect(page).to have_css('[data-testid="formatting-bubble-menu"]')
+      expect(page).to have_css('[data-testid="formatting-bubble-menu"]')
+    end
+
+    it 'does not show a formatting bubble menu for code' do
+      find(content_editor_testid).send_keys 'This is a `code`'
+      find(content_editor_testid).send_keys [:shift, :left]
+
+      expect(page).not_to have_css('[data-testid="formatting-bubble-menu"]')
+    end
+  end
+
+  describe 'code block bubble menu' do
+    it 'shows a code block bubble menu for a code block' do
+      find(content_editor_testid).send_keys '```js ' # trigger input rule
+      find(content_editor_testid).send_keys 'var a = 0'
+      find(content_editor_testid).send_keys [:shift, :left]
+
+      expect(page).not_to have_css('[data-testid="formatting-bubble-menu"]')
+      expect(page).to have_css('[data-testid="code-block-bubble-menu"]')
+    end
+
+    it 'sets code block type to "javascript" for `js`' do
+      find(content_editor_testid).send_keys '```js '
+      find(content_editor_testid).send_keys 'var a = 0'
+
+      expect(find('[data-testid="code-block-bubble-menu"]')).to have_text('Javascript')
+    end
+
+    it 'sets code block type to "Custom (nomnoml)" for `nomnoml`' do
+      find(content_editor_testid).send_keys '```nomnoml '
+      find(content_editor_testid).send_keys 'test'
+
+      expect(find('[data-testid="code-block-bubble-menu"]')).to have_text('Custom (nomnoml)')
+    end
   end
 end