"isJapanese" check move (#730)

* Move isStringPartiallyJapanese out of ClipboardMonitor

* Create isStringPartiallyJapanese function

* Add textMayBeTranslatable

* Rename API function

* Rename internal function

* Add helper

* Update translatable check

* Pass language to TextScanner

* Pass language explicitly

* Use textMayBeTranslatable

* No redundant translatable check

* Update eslint

* Remove double newline

* Collapse

* Rename

1 files changed, 20 insertions, 12 deletions

diff --git a/ext/js/display/display-generator.js b/ext/js/display/display-generator.js
index 22912e9f..0b3236e9 100644
--- a/ext/js/display/display-generator.js
+++ b/ext/js/display/display-generator.js
@@ -20,7 +20,8 @@ import {ExtensionError} from '../core/extension-error.js';
 import {isObject} from '../core/utilities.js';
 import {getDisambiguations, getGroupedPronunciations, getTermFrequency, groupKanjiFrequencies, groupTermFrequencies, groupTermTags, isNonNounVerbOrAdjective} from '../dictionary/dictionary-data-util.js';
 import {HtmlTemplateCollection} from '../dom/html-template-collection.js';
-import {distributeFurigana, getKanaMorae, getPitchCategory, isCodePointKanji, isStringPartiallyJapanese} from '../language/ja/japanese.js';
+import {distributeFurigana, getKanaMorae, getPitchCategory, isCodePointKanji} from '../language/ja/japanese.js';
+import {getLanguageFromText} from '../language/text-utilities.js';
 import {createPronunciationDownstepPosition, createPronunciationGraph, createPronunciationText} from './sandbox/pronunciation-generator.js';
 import {StructuredContentGenerator} from './sandbox/structured-content-generator.js';
 
@@ -991,12 +992,7 @@ export class DisplayGenerator {
      * @param {string} [language]
      */
     _setTextContent(node, value, language) {
-        if (typeof language === 'string') {
-            node.lang = language;
-        } else if (isStringPartiallyJapanese(value)) {
-            node.lang = 'ja';
-        }
-
+        this._setElementLanguage(node, language, value);
         node.textContent = value;
     }
 
@@ -1008,11 +1004,7 @@ export class DisplayGenerator {
     _setMultilineTextContent(node, value, language) {
         // This can't just call _setTextContent because the lack of <br> elements will
         // cause the text to not copy correctly.
-        if (typeof language === 'string') {
-            node.lang = language;
-        } else if (isStringPartiallyJapanese(value)) {
-            node.lang = 'ja';
-        }
+        this._setElementLanguage(node, language, value);
 
         let start = 0;
         while (true) {
@@ -1029,6 +1021,22 @@ export class DisplayGenerator {
     }
 
     /**
+     * @param {HTMLElement} element
+     * @param {string|undefined} language
+     * @param {string} content
+     */
+    _setElementLanguage(element, language, content) {
+        if (typeof language === 'string') {
+            element.lang = language;
+        } else {
+            const language2 = getLanguageFromText(content);
+            if (language2 !== null) {
+                element.lang = language2;
+            }
+        }
+    }
+
+    /**
      * @param {string} reading
      * @param {import('dictionary').TermPronunciation[]} termPronunciations
      * @param {string[]} wordClasses