🐛 Bug Report

Wrangler errors without a package.json for JavaScript projects, yet there is no reason to require it.

Environment

• output of wrangler -V: wrangler 1.12.3
• contents of wrangler.toml: type=javascript

Steps to reproduce

1. Create a hello world script with type=javascript
2. Run wrangler dev or wrangler publish
3. See the error `Error: Your Java

Describe the problem:

The slash at the end not auto resolving.
For example
https://cool-bio-flareact-styled.coolbio.workers.dev/subh/ will throw an error
but https://cool-bio-flareact-styled.coolbio.workers.dev/subh is accessible.

Link to a minimal reproduction:

https://github.com/subhendukundu/cool-bio-flareact-styled