declarationMap not working

[hb1998]

declarationMap is ts compiler option which I use in a monorepo for Go to Defenition support in vscode.
I use gulp and gulp-typescript to compile typescript and in the docs they have mentioned

Sourcemap options (sourceMap, inlineSourceMap, inlineSources, sourceRoot, declarationMap) - Use gulp-sourcemaps instead.

but after adding gulp-sourcemap its still not generating the files.

this is what is generated after direct tsc compilation

with gulp-typescript and gulp-sourcemaps

this is my gulp script