Source maps do not work when using a base path with the development server

[agubler]

Bug

Source maps and hmr do not work when running the development server (--serve option) when the application is configured with a base path in the .dojorc

.dojorc

{
    "build-app": {
        "base": "/app/"
    }
}

Build command

dojo build -m dev -w -s

Navigating to http://localhost:9999/app

Expected behavior:

The application should run on the base url and support sourcemaps and hmr (hot module reload)

Actual behavior:

sourcemaps and hmr do not work as expected.

[agubler]

This should be fixed by #360