diff --git a/src/node/utils/LibreOffice.js b/src/node/utils/LibreOffice.js
index 74496cabd..914d79a4b 100644
--- a/src/node/utils/LibreOffice.js
+++ b/src/node/utils/LibreOffice.js
@@ -1,3 +1,4 @@
+'use strict';
 /**
  * Controls the communication with LibreOffice
  */
@@ -24,52 +25,9 @@ const path = require('path');
 const settings = require('./Settings');
 const spawn = require('child_process').spawn;
 
-// Conversion tasks will be queued up, so we don't overload the system
-const queue = async.queue(doConvertTask, 1);
-
 const libreOfficeLogger = log4js.getLogger('LibreOffice');
 
-/**
- * Convert a file from one type to another
- *
- * @param  {String}     srcFile     The path on disk to convert
- * @param  {String}     destFile    The path on disk where the converted file should be stored
- * @param  {String}     type        The type to convert into
- * @param  {Function}   callback    Standard callback function
- */
-exports.convertFile = function (srcFile, destFile, type, callback) {
-  // Used for the moving of the file, not the conversion
-  const fileExtension = type;
-
-  if (type === 'html') {
-    // "html:XHTML Writer File:UTF8" does a better job than normal html exports
-    if (path.extname(srcFile).toLowerCase() === '.doc') {
-      type = 'html';
-    }
-    // PDF files need to be converted with LO Draw ref https://github.com/ether/etherpad-lite/issues/4151
-    if (path.extname(srcFile).toLowerCase() === '.pdf') {
-      type = 'html:XHTML Draw File';
-    }
-  }
-
-  // soffice can't convert from html to doc directly (verified with LO 5 and 6)
-  // we need to convert to odt first, then to doc
-  // to avoid `Error: no export filter for /tmp/xxxx.doc` error
-  if (type === 'doc') {
-    queue.push({
-      srcFile,
-      destFile: destFile.replace(/\.doc$/, '.odt'),
-      type: 'odt',
-      callback() {
-        queue.push({srcFile: srcFile.replace(/\.html$/, '.odt'), destFile, type, callback, fileExtension});
-      },
-    });
-  } else {
-    queue.push({srcFile, destFile, type, callback, fileExtension});
-  }
-};
-
-function doConvertTask(task, callback) {
+const doConvertTask = (task, callback) => {
   const tmpDir = os.tmpdir();
 
   async.series([
@@ -77,8 +35,10 @@ function doConvertTask(task, callback) {
      * use LibreOffice to convert task.srcFile to another format, given in
      * task.type
      */
-    function (callback) {
-      libreOfficeLogger.debug(`Converting ${task.srcFile} to format ${task.type}. The result will be put in ${tmpDir}`);
+    (callback) => {
+      libreOfficeLogger.debug(
+          `Converting ${task.srcFile} to format ${task.type}. The result will be put in ${tmpDir}`
+      );
       const soffice = spawn(settings.soffice, [
         '--headless',
         '--invisible',
@@ -112,7 +72,7 @@ function doConvertTask(task, callback) {
 
       soffice.on('exit', (code) => {
         clearTimeout(hangTimeout);
-        if (code != 0) {
+        if (code !== 0) {
           // Throw an exception if libreoffice failed
           return callback(`LibreOffice died with exit code ${code} and message: ${stdoutBuffer}`);
         }
@@ -123,10 +83,10 @@ function doConvertTask(task, callback) {
     },
 
     // Move the converted file to the correct place
-    function (callback) {
+    (callback) => {
       const filename = path.basename(task.srcFile);
-      const sourceFilename = `${filename.substr(0, filename.lastIndexOf('.'))}.${task.fileExtension}`;
-      const sourcePath = path.join(tmpDir, sourceFilename);
+      const sourceFile = `${filename.substr(0, filename.lastIndexOf('.'))}.${task.fileExtension}`;
+      const sourcePath = path.join(tmpDir, sourceFile);
       libreOfficeLogger.debug(`Renaming ${sourcePath} to ${task.destFile}`);
       fs.rename(sourcePath, task.destFile, callback);
     },
@@ -137,4 +97,55 @@ function doConvertTask(task, callback) {
     // Invoke the callback for the task
     task.callback(err);
   });
-}
+};
+
+// Conversion tasks will be queued up, so we don't overload the system
+const queue = async.queue(doConvertTask, 1);
+
+/**
+ * Convert a file from one type to another
+ *
+ * @param  {String}     srcFile     The path on disk to convert
+ * @param  {String}     destFile    The path on disk where the converted file should be stored
+ * @param  {String}     type        The type to convert into
+ * @param  {Function}   callback    Standard callback function
+ */
+exports.convertFile = (srcFile, destFile, type, callback) => {
+  // Used for the moving of the file, not the conversion
+  const fileExtension = type;
+
+  if (type === 'html') {
+    // "html:XHTML Writer File:UTF8" does a better job than normal html exports
+    if (path.extname(srcFile).toLowerCase() === '.doc') {
+      type = 'html';
+    }
+    // PDF files need to be converted with LO Draw ref https://github.com/ether/etherpad-lite/issues/4151
+    if (path.extname(srcFile).toLowerCase() === '.pdf') {
+      type = 'html:XHTML Draw File';
+    }
+  }
+
+  // soffice can't convert from html to doc directly (verified with LO 5 and 6)
+  // we need to convert to odt first, then to doc
+  // to avoid `Error: no export filter for /tmp/xxxx.doc` error
+  if (type === 'doc') {
+    queue.push({
+      srcFile,
+      destFile: destFile.replace(/\.doc$/, '.odt'),
+      type: 'odt',
+      callback: () => {
+        queue.push(
+            {
+              srcFile: srcFile.replace(/\.html$/, '.odt'),
+              destFile,
+              type,
+              callback,
+              fileExtension,
+            }
+        );
+      },
+    });
+  } else {
+    queue.push({srcFile, destFile, type, callback, fileExtension});
+  }
+};