Use guesslang-js for language auto detection instead of Highlight.js

Should (hopefully) reduce false positives.

public/langdetect-worker.js

@@ -1,21 +1,22 @@
-importScripts("highlight.min.js")
+importScripts("guesslang.min.js")
 
-const HIGHLIGHTJS_LANGUAGES = [
-    "json", 
-    "python", 
-    "javascript", 
-    "html", 
-    "sql", 
-    "java", 
-    "plaintext", 
-    "cpp", 
-    "php", 
-    "css", 
-    "markdown",
+GUESSLANG_LANGUAGES = [
+    "json",
+    "py",
+    "js",
+    "html",
+    "sql",
+    "java",
+    "cpp",
+    "php",
+    "css",
     "xml",
-    "rust",
+    "rs",
+    "md",
 ]
 
+const guessLang = new self.GuessLang()
+
 onmessage = (event) => {
     //console.log("worker received message:", event.data)
     //importScripts("../../lib/highlight.min.js")
@@ -34,10 +35,9 @@ onmessage = (event) => {
         try {
             if (typeof JSON.parse(trimmedContent) === "object") {
                 postMessage({
-                    highlightjs: {
+                    guesslang: {
                         language: "json",
-                        relevance: 100,
-                        illegal: false,
+                        confidence: 1.0,
                     },
                     content: content,
                     idx: event.data.idx,
@@ -49,14 +49,39 @@ onmessage = (event) => {
         }
     }
 
-    const result = self.hljs.highlightAuto(content, HIGHLIGHTJS_LANGUAGES);
-    postMessage({
-        highlightjs: {
-            language: result.language,
-            relevance: result.relevance,
-            illegal: result.illegal,
-        },
-        content: content,
-        idx: event.data.idx,
+    //let startTime = performance.now()
+    guessLang.runModel(content).then((result) => {
+        //const duration = performance.now() - startTime
+        //console.log("Guessing language done:", result, result[0]?.languageId, result[0]?.confidence)
+        //console.log("Guessing language took", duration, "ms")
+
+        if (result.length > 0) {
+            // for the language that is most likely according to GuessLang we have a lower threshold (0.15)
+            const lang = result[0]
+            if (GUESSLANG_LANGUAGES.includes(lang.languageId) && lang.confidence > 0.15) {
+                postMessage({
+                    guesslang: {
+                        language: lang.languageId,
+                        confidence: lang.confidence,
+                    },
+                    content: content,
+                    idx: event.data.idx,
+                })
+                return
+            }
+        }
+        for (let lang of result) {
+            if (GUESSLANG_LANGUAGES.includes(lang.languageId) && lang.confidence > 0.5) {
+                postMessage({
+                    guesslang: {
+                        language: lang.languageId,
+                        confidence: lang.confidence,
+                    },
+                    content: content,
+                    idx: event.data.idx,
+                })
+                return
+            }
+        }
     })
 }

src/editor/language-detection/autodetect.js

@@ -7,7 +7,7 @@ import { LANGUAGES } from "../languages";
 import { changeLanguageTo } from "../block/commands";
 import { LANGUAGE_CHANGE } from "../annotation";
 
-const HIGHLIGHTJS_TO_TOKEN = Object.fromEntries(LANGUAGES.map(l => [l.highlightjs,l.token]))
+const GUESSLANG_TO_TOKEN = Object.fromEntries(LANGUAGES.map(l => [l.guesslang,l.token]))
 
 
 export function languageDetection(getView) {
@@ -17,29 +17,27 @@ export function languageDetection(getView) {
     const detectionWorker = new Worker('langdetect-worker.js?worker');
     detectionWorker.onmessage = (event) => {
         //console.log("event:", event.data)
-        if (!event.data.highlightjs.language) {
+        if (!event.data.guesslang.language) {
             return
         }
         const view = getView()
         const state = view.state
         const block = getActiveNoteBlock(state)
-        const newLang = HIGHLIGHTJS_TO_TOKEN[event.data.highlightjs.language]
+        const newLang = GUESSLANG_TO_TOKEN[event.data.guesslang.language]
         if (block.language.auto === true && block.language.name !== newLang) {
-            console.log("New auto detected language:", newLang, "Relevance:", event.data.highlightjs.relevance)
-            if (event.data.highlightjs.relevance >= 7) {
-                let content = state.doc.sliceString(block.content.from, block.content.to)
-                const threshold = content.length * 0.1
-                if (levenshtein_distance(content, event.data.content) <= threshold) {
-                    // the content has not changed significantly so it's safe to change the language
-                    if (redoDepth(state) === 0) {
-                        console.log("Changing language to", newLang)
-                        changeLanguageTo(state, view.dispatch, block, newLang, true)
-                    } else {
-                        console.log("Not changing language because the user has undo:ed and has redo history")
-                    }
+            console.log("New auto detected language:", newLang, "Confidence:", event.data.guesslang.confidence)
+            let content = state.doc.sliceString(block.content.from, block.content.to)
+            const threshold = content.length * 0.1
+            if (levenshtein_distance(content, event.data.content) <= threshold) {
+                // the content has not changed significantly so it's safe to change the language
+                if (redoDepth(state) === 0) {
+                    console.log("Changing language to", newLang)
+                    changeLanguageTo(state, view.dispatch, block, newLang, true)
                 } else {
-                    console.log("Content has changed significantly, not setting new language")
+                    console.log("Not changing language because the user has undo:ed and has redo history")
                 }
+            } else {
+                console.log("Content has changed significantly, not setting new language")
             }
         }
     }

src/editor/languages.js

@@ -14,24 +14,24 @@ import { rustLanguage } from "@codemirror/lang-rust"
 
 
 class Language {
-    constructor(token, name, parser, highlightjs, supportsFormat=false) {
+    constructor(token, name, parser, guesslang, supportsFormat=false) {
         this.token = token
         this.name = name
         this.parser = parser
-        this.highlightjs = highlightjs
+        this.guesslang = guesslang
         this.supportsFormat = supportsFormat
     }
 }
 
 export const LANGUAGES = [
-    new Language("text", "Plain Text", null, "plaintext"),
+    new Language("text", "Plain Text", null, null),
     new Language("math", "Math", null, null),
-    new Language("javascript", "JavaScript", javascriptLanguage.parser, "javascript", true),
+    new Language("javascript", "JavaScript", javascriptLanguage.parser, "js", true),
     new Language("json", "JSON", jsonLanguage.parser, "json", true),
-    new Language("python", "Python", pythonLanguage.parser, "python"),
+    new Language("python", "Python", pythonLanguage.parser, "py"),
     new Language("html", "HTML", htmlLanguage.parser, "html", true),
     new Language("sql", "SQL", StandardSQL.language.parser, "sql"),
-    new Language("markdown", "Markdown", markdownLanguage.parser, "markdown", true),
+    new Language("markdown", "Markdown", markdownLanguage.parser, "md", true),
     new Language("java", "Java", javaLanguage.parser, "java"),
     //new Language("lezer", "Lezer", lezerLanguage.parser, "lezer"),
     new Language("php", "PHP", phpLanguage.parser, "php"),