search resolution option (#436)

* add search resolution setting

* move finding next substring to method

* use regex literal

* fix comments

* fix comments

* add options update function

* update test

1 files changed, 20 insertions, 2 deletions

diff --git a/ext/js/language/translator.js b/ext/js/language/translator.js
index 733955c2..36ed8b43 100644
--- a/ext/js/language/translator.js
+++ b/ext/js/language/translator.js
@@ -329,8 +329,12 @@ export class Translator {
                 text2 = jp.collapseEmphaticSequences(text2, collapseEmphaticFull, sourceMap);
             }
 
-            for (let i = text2.length; i > 0; --i) {
-                const source = text2.substring(0, i);
+            for (
+                let source = text2, i = text2.length;
+                i > 0;
+                i = this._getNextSubstringLength(options.searchResolution, i, source)
+            ) {
+                source = text2.substring(0, i);
                 if (used.has(source)) { break; }
                 used.add(source);
                 const rawSource = sourceMap.source.substring(0, sourceMap.getSourceLength(i));
@@ -343,6 +347,20 @@ export class Translator {
     }
 
     /**
+     * @param {string} searchResolution
+     * @param {number} currentLength
+     * @param {string} source
+     * @returns {number}
+     */
+    _getNextSubstringLength(searchResolution, currentLength, source) {
+        if (searchResolution === 'word') {
+            return source.search(/[^\p{Letter}][\p{Letter}\p{Number}]*$/u);
+        } else {
+            return currentLength - 1;
+        }
+    }
+
+    /**
      * @param {string} text
      * @param {TextSourceMap} sourceMap
      * @param {import('translation').FindTermsTextReplacement[]} replacements