javascript source map : keeping map file local only to debug production javascript

Question

I would like to debug production website, but I don't want to upload the map file on the server (for privacy reason, because it is public right ?).

Is it possible ?

Answer 1

I don't believe any browsers currently allow loading source maps ondemand from local files, so you have to put the sourcemaps online somehow.

One solution could be to create a .htaccess file (or something similar, if you aren't using Apache) that restricts access to the sourcemap (and the original source files) to clients that aren't from your local network.

You should realize though, that if you want to prevent access to the sourcemaps for security reasons, then all you will achieve is a false sense of safety. Javascript is public, and even if it is minified and encrypted, it is fairly easy to unencrypt it. Do not put any sensitive data in your javascript. Not even if you minify and encrypt it.

Answer 2

Following might be useful for you

Multi-level Source Maps - The CSS Ninja

The link also explains using UglifyJS2 with which an input source map can be specified. However, I have not tested with a local input source

Also, you can try hosting the file on local and changing your hosts file to point something like local.mydomain.com to localhost. And then specify local.mydomain.com/js/my-orig-js-file.js as the Source Root

Answer 3

Another solution is to upload the map file and the minified js on the server and keep the original js file locally. Then modify your map file in something like this:

{
    "version":3,
    "sources":["http://localhost/library.js"],
    "names":["example","console","log"],
    "mappings":"AAAA,QAASA,YACRC,QAAQC,IAAI","file":"script.min.js"
}