Updated lib/index.js to be lint-happy. Added promise-based API for `.…

…mv` method. This fixes #42

lib/index.js

@@ -14,8 +14,9 @@ module.exports = function(options) {
   options = options || {};
 
   return function(req, res, next) {
-    if (!hasBody(req) || !hasAcceptableMethod(req) || !hasAcceptableMime(req))
+    if (!hasBody(req) || !hasAcceptableMethod(req) || !hasAcceptableMime(req)) {
       return next();
+    }
 
     processMultipart(options, req, res, next);
   };
@@ -56,11 +57,13 @@ function processMultipart(options, req, res, next) {
 
     let prev = req.body[fieldname];
 
-    if (!prev)
+    if (!prev) {
       return req.body[fieldname] = val;
+    }
 
-    if (Array.isArray(prev))
+    if (Array.isArray(prev)) {
       return prev.push(val);
+    }
 
     req.body[fieldname] = [prev, val];
   });
@@ -73,34 +76,39 @@ function processMultipart(options, req, res, next) {
     file.on('data', function(data) {
       buffers.push(data);
 
-      if (options.debug)
+      if (options.debug) {
         return console.log('Uploading %s -> %s', fieldname, filename);
+      }
     });
 
     file.on('end', function() {
-      if (!req.files)
+      if (!req.files) {
         req.files = {};
+      }
 
       const buf = Buffer.concat(buffers);
       // see: https://github.com/richardgirges/express-fileupload/issues/14
       // firefox uploads empty file in case of cache miss when f5ing page.
       // resulting in unexpected behavior. if there is no file data, the file is invalid.
-      if (!buf.length)
+      if (!buf.length) {
         return;
+      }
 
       if (options.safeFileNames) {
         let maxExtensionLength = 3;
         let extension = '';
 
-        if (typeof options.safeFileNames === 'object')
+        if (typeof options.safeFileNames === 'object') {
           safeFileNameRegex = options.safeFileNames;
+        }
 
         maxExtensionLength = parseInt(options.preserveExtension);
         if (options.preserveExtension || maxExtensionLength === 0) {
-          if (isNaN(maxExtensionLength))
+          if (isNaN(maxExtensionLength)) {
             maxExtensionLength = 3;
-          else
+          } else {
             maxExtensionLength = Math.abs(maxExtensionLength);
+          }
 
           let filenameParts = filename.split('.');
           let filenamePartsLen = filenameParts.length;
@@ -126,20 +134,44 @@ function processMultipart(options, req, res, next) {
         data: buf,
         encoding: encoding,
         mimetype: mime,
-        mv: function(path, callback) {
-          let fstream = fs.createWriteStream(path);
+        mv: function(path, callback = null) {
+          // Callback is passed in, use the callback API
+          if (callback) {
+            doMove(
+              () => {
+                callback(null);
+              },
+              (error) => {
+                callback(error);
+              }
+            );
+
+          // Otherwise, return a promise
+          } else {
+            return new Promise((resolve, reject) => {
+              doMove(resolve, reject);
+            });
+          }
 
-          streamifier.createReadStream(buf).pipe(fstream);
+          /**
+           * Local function that moves the file to a different location on the filesystem
+           * Takes two function arguments to make it compatible w/ Promise or Callback APIs
+           * @param {Function} successFunc 
+           * @param {Function} errorFunc 
+           */
+          function doMove(successFunc, errorFunc) {
+            const fstream = fs.createWriteStream(path);
 
-          fstream.on('error', function(error) {
-            if (callback)
-              callback(error);
-          });
+            streamifier.createReadStream(buf).pipe(fstream);
 
-          fstream.on('close', function() {
-            if (callback)
-              callback(null);
-          });
+            fstream.on('error', function(error) {
+              errorFunc(error);
+            });
+
+            fstream.on('close', function() {
+              successFunc();
+            });
+          }
         }
       };
 
@@ -148,10 +180,11 @@ function processMultipart(options, req, res, next) {
         req.files[fieldname] = newFile;
       } else {
         // Array fields
-        if (req.files[fieldname] instanceof Array)
+        if (req.files[fieldname] instanceof Array) {
           req.files[fieldname].push(newFile);
-        else
+        } else {
           req.files[fieldname] = [req.files[fieldname], newFile];
+        }
       }
     });