How to generate sourcemap that contains relative 'sources' and 'files', as tsc does?

I am building a typescript nodejs project using VSCode.

The gulp code is:

var tsProject = ts.createProject(tsConfigFile);
  return tsProject.src()
    .pipe(sourcemaps.init())
    .pipe(ts(tsProject))
    .js
    .pipe(sourcemaps.write('.', {includeContent: false, sourceRoot: ''})) 
    .pipe(gulp.dest('.'));

For files in subdirectories, such as routes/users.ts, the content of the generated users.js.map is

{"version":3,"sources":["routes/users.ts"],"names":[], "mappings":"...","file":"routes/users.js","sourceRoot":""}

The breakpoint is not working in VSCode, so I tried to use tsc to generate the sourcemap. The sourcemap generated by tsc is

{"version":3,"file":"users.js","sourceRoot":"","sources":["users.ts"],"names":[], "mappings":"..."}

and it works fine in VSCode.

So how to config gulp-sourcemaps to generate the sourcemap as the tsc does?

[Nepoxx]

This is what I have and it works with VSCode although the output is not exactly like TSC’s output:

return gulp.src(['typings/index.d.ts', 'src/**/*.ts'])
    .pipe(sourcemaps.init())
    .pipe(tsProject(ts.reporter.longReporter()))
    .js
    .pipe(sourcemaps.write({
      mapSources: (path) => path, // This affects the "sources" attribute even if it is a no-op. I don't know why.
      sourceRoot: (file) => {
        return path.relative(file.relative, path.join(file.cwd, 'src'));
      }
    }))
    .pipe(gulp.dest('dist'));

[gravaton]

I have a similar issue, although the differences are a little more troubling - if I write out sourcemaps with the following invocation:

.pipe(sourcemaps.write('.')

The sourcemaps have the following at the end:

"sourceRoot":"/source"

How this gets there is baffling to me as no such directory is used anywhere in my compilation steps.