JS SourceMaps for Perl

Since everyone deploys minified/combined wads of JS goo, debugging errors in the field can be a bitch. The idea behind sourcemaps is to provide a way for web developers to debug their code once deployed. Sourcemaps provide a compact index into the minified source that lets you map the file/line/col given to you in a JS runtime error thrown by your minified JS back into the real file/line/col in your source code.

A decent albeit dated tutorial can be found here: https://www.html5rocks.com/en/tutorials/developertools/sourcemaps/

The use case for this module is a server-side component in Perl that receives JS runtime error information somehow from a web application's JS front end. You generally have the source map available on the server already but there is a discover function in JS::SourceMap that will search JS code for a pointer to its source map as per convention. You'll have to fetch the URL that discover finds yourself, though.

This module is inspired by https://github.com/mattrobenolt/python-sourcemap It hews fairly closely to that implementation. I brought over all of the same test inputs (t/fixtures) and all of the tests that made sense (no iterators in Perl).