Meteor and the 'Uncaught SyntaxError: Unexpected token Y' error

Posted by Marcus Hammarberg on June 5, 2015
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Right now my head is spinning from the awesomeness that is Meteor. I am somewhere in between “This is too much magic to really believe…” and “Wow - why have I ever built anything with anything else before!”.

Just a short little post about an error that have caused me problems. Here’s the error, that most likely pops up in your browser console:

Uncaught SyntaxError: Unexpected token Y

TL;DR - Reload your browser

This is a Javascript parsing error, when trying to parse a very helpful error message from Meteor. Just reload the page and you’ll see the message.

Longer … but still short and sweet

The background

Meteor is super helpful in many ways. Creating an app is just three small steps:

meteor create myPrecious
cd myPrecious
meteor

That last one is very special. That starts the application and live reloads the page for every change you make. So you litterally write that meteor command once and then open a new tab / window where you install packages, add files etc. It’s always running.

The moment you make any changes in your application any browser pointing to it is reloaded too. Yes, Meteor has built in LiveReload.

The tripping-up

But this helpfulness is what trips me up. Because now Meteor is running away in the background and I never look there again. When I mess up a

=> Errors prevented startup:
   
   While building the application:
   client/components/poll-form.html:26: bad formatting in HTML template

Instead I only get a blank page in my browser after the change, and when I look in the console I see a JavaScript error: Uncaught SyntaxError: Unexpected token Y.

Fix it with reload. Yes, manually!

Now, this is the first time you actually need to reload the browser manually. Which quite frankly, feels really cumbersome (!) after being spoiled by Meteor all this time. Imagine that.

Once you reload the browser all is clear and helpful again. This is the text that Meteor sends to the client.

Your app is crashing. Here's the latest log.

=> Meteor server restarted
Errors prevented startup:

While building the application:
client/components/poll-form.html:25: bad formatting in HTML template

Your application has errors. Waiting for file change.

The Unexpected token Y is the start of Your, that JavaScript tries to make sense of.

Summary

Should you see the Uncaught SyntaxError: Unexpected token Y remember the old days and just reload the browser window. It’s a hassle I know :)



Published by Marcus Hammarberg on Last updated