add JSON response for errors when using JS

lib/middlewares.js

@@ -1,7 +1,19 @@
 const FBURLError = () => new Error('Not a valid Facebook URL!')
 
+const sendJSON = (req) => {
+  return req.accepts().includes('application/json')
+}
+
 const genericErrorHandler = (err, req, res, next) => {
   console.error(err.stack)
+
+  if (sendJSON(req)) {
+    res
+      .status(500)
+      .send({ error: err.toString() })
+    return
+  }
+
   res
     .status(500)
     .render('error', { error: err.toString() })

lib/public/scripts.js

@@ -172,7 +172,6 @@
   }
 
   const handleError = (error) => {
-    console.error(error)
     finishedRequest()
     setStatusError(error)
   }
@@ -182,11 +181,16 @@
       fetch('/download', {
         method: 'POST',
         headers: {
+          'Accept': 'text/calendar, application/json',
           'Content-Type': 'application/x-www-form-urlencoded',
         },
         body: data,
       }).then((response) => {
-        if (response.status === 500) {
+        if (response.status !== 200) {
+          if (response.body.constructor === ReadableStream) {
+            response.json().then((json) => reject(json.error || response.statusText))
+            return
+          }
           reject(response.statusText)
           return
         }
@@ -195,6 +199,7 @@
       }).catch(reject)
     })
   }
+  window.postURL = postURL
 
   const form = document.querySelector('form')
   const submitButton = document.querySelector("#submit")

lib/views/index.ejs

@@ -23,11 +23,11 @@
         into your calendar.
       </p>
 
-      <div class="row">
       <form action='/download' method='POST' id="form">
         <input id="url" type='text' name='url' placeholder='Paste / type FB event URL here...' />
         <input id="submit" type='submit' value='Submit' />
       </form>
+
       <div id="status">
         <div class="status-item" id="network">
           Fetching file...
@@ -40,7 +40,6 @@
         <div class="status-item" id="service-worker">
         </div>
       </div>
-      </div>
 
       <br />