This is a temporary workaround to support bundling with sourcemaps in Deno. It's a drop-in replacement for the deno bundle CLI that uses the Deno.emit API to generate and inline the bundle's sourcemap.
deno install --unstable --allow-read --allow-net --allow-write -f https://deno.land/x/deno_bundle/cli.js
deno_bundle source_file [out_file]