When an input sourcemap is given, the result's sourcemap will be merged with it, so it points back to the input sourcemap's sources (aka the original source).
Bonus: If //# sourceMappingURL exists and the filename option is defined, load the source map and treat it as an input sourcemap automatically.
When an input sourcemap is given, the result's sourcemap will be merged with it, so it points back to the input sourcemap's sources (aka the original source).
Bonus: If
//# sourceMappingURLexists and thefilenameoption is defined, load the source map and treat it as an input sourcemap automatically.