diff --git a/src/main/core/entry.js b/src/main/core/entry.js
index fb4dce13..da2837c2 100644
--- a/src/main/core/entry.js
+++ b/src/main/core/entry.js
@@ -4,43 +4,13 @@
  * Licensed under MIT
  */
 
-import entryGeneratorJa from "./entry/ja";
-import entryGeneratorEn from "./entry/en";
-
-const generators = {
-  en: entryGeneratorEn,
-  ja: entryGeneratorJa,
-  default: entryGeneratorEn,
-};
-
-let languageDetector = (text) => (isEnglishText(text) ? "en" : "ja");
-
-const build = (text, withCapitalized, mustIncludeOriginalText) => {
-  const lang = languageDetector(text);
-  const generator = generators[lang] ?? generators.default;
-  const entries = generator(text, withCapitalized, mustIncludeOriginalText);
-  return { entries, lang };
-};
-
-const isEnglishText = (str) => {
-  let result = true;
-  for (let i = 0; i < str.length; i++) {
-    const code = str.charCodeAt(i);
-    const isEnglishLike = (0x20 <= code && code <= 0x7e) || code === 0x2011 || code === 0x200c;
-    if (!isEnglishLike) {
-      result = false;
-      break;
-    }
-  }
-  return result;
-};
-
-const registerGenerator = (lang, generator) => {
-  generators[lang] = generator;
-};
-
-const registerLanguageDetector = (detector) => {
-  languageDetector = detector;
+const build = (languageDetector, generators) => {
+  return (text, withCapitalized, mustIncludeOriginalText) => {
+    const lang = languageDetector(text);
+    const generator = generators[lang] ?? generators.default;
+    const entries = generator(text, withCapitalized, mustIncludeOriginalText);
+    return { entries, lang };
+  };
 };
 
-export default { build, registerGenerator, registerLanguageDetector };
+export default { build };
diff --git a/src/main/core/entry/default.js b/src/main/core/entry/default.js
new file mode 100644
index 00000000..772be3bc
--- /dev/null
+++ b/src/main/core/entry/default.js
@@ -0,0 +1,37 @@
+/**
+ * Mouse Dictionary (https://github.com/wtetsu/mouse-dictionary/)
+ * Copyright 2018-present wtetsu
+ * Licensed under MIT
+ */
+
+import entry from "../entry";
+import entryGeneratorJa from "./ja";
+import entryGeneratorEn from "./en";
+
+// Can add other languages here
+const generators = {
+  en: entryGeneratorEn,
+  ja: entryGeneratorJa,
+  default: entryGeneratorEn,
+};
+
+let languageDetector = (text) => (isEnglishText(text) ? "en" : "ja");
+
+const isEnglishText = (str) => {
+  let result = true;
+  for (let i = 0; i < str.length; i++) {
+    const code = str.charCodeAt(i);
+    const isEnglishLike = (0x20 <= code && code <= 0x7e) || code === 0x2011 || code === 0x200c;
+    if (!isEnglishLike) {
+      result = false;
+      break;
+    }
+  }
+  return result;
+};
+
+const build = () => {
+  return entry.build(languageDetector, generators);
+};
+
+export default build;
diff --git a/src/main/core/events.js b/src/main/core/events.js
index 6dea85ad..3701d66d 100644
--- a/src/main/core/events.js
+++ b/src/main/core/events.js
@@ -6,6 +6,7 @@
 
 import config from "./config";
 import rule from "./rule";
+import entryDefault from "./entry/default";
 import Lookuper from "./lookuper";
 import dom from "../lib/dom";
 import traverser from "../lib/traverser";
@@ -19,7 +20,7 @@ const attach = async (settings, dialog, doUpdateContent) => {
   let enableDefault = true;
 
   const traverse = traverser.build(rule.doLetters, settings.parseWordsLimit);
-  const lookuper = new Lookuper(settings, doUpdateContent);
+  const lookuper = new Lookuper(settings, entryDefault(), doUpdateContent);
 
   const draggable = new Draggable(settings.normalDialogStyles, settings.movingDialogStyles);
   draggable.events.change = (e) => config.savePosition(e);
diff --git a/src/main/core/lookuper.js b/src/main/core/lookuper.js
index cfeb4a3e..b29ab785 100644
--- a/src/main/core/lookuper.js
+++ b/src/main/core/lookuper.js
@@ -4,7 +4,6 @@
  * Licensed under MIT
  */
 
-import entry from "./entry";
 import Generator from "./generator";
 import dom from "../lib/dom";
 import storage from "../lib/storage";
@@ -14,9 +13,10 @@ import utils from "../lib/utils";
 const TEXT_LENGTH_LIMIT = 128;
 
 export default class Lookuper {
-  constructor(settings, doUpdateContent) {
+  constructor(settings, doBuildEntry, doUpdateContent) {
     this.lookupWithCapitalized = settings.lookupWithCapitalized;
     this.doUpdateContent = doUpdateContent;
+    this.doBuildEntry = doBuildEntry;
 
     this.lastText = null;
     this.aimed = false;
@@ -127,7 +127,7 @@ export default class Lookuper {
     const langs = [];
     for (let i = 0; i < textList.length; i++) {
       const text = textList[i];
-      const { entries, lang } = entry.build(text, withCapitalized, includeOrgText);
+      const { entries, lang } = this.doBuildEntry(text, withCapitalized, includeOrgText);
       console.info(`${entries.join(",")}`);
       console.info(`${entries.length}`);