find-dependencies.coffee

# ...

module.exports = ->

  output = new stream.Transform(objectMode: true)

  output._transform = (file, enc, callback) ->

    # Pass this file along (do this *before* finding dependencies to preserve load order)
    output.push(file)
    
    # Find include statements
    includes = file.contents.match(includeStatementPattern)

    for statement in includes
    
      includedFiles = resolveIncludedFilepaths(statement, file)
      
      for f in includedFiles
        # Take an included file, write back into this same stream to recursively check
        # for includes.
        output.write(f)
        
  return output

gulpfile.coffee

findDependencies = require('find-dependencies')

gulp.task 'scripts', ->
  gulp.src([ 'app/index.coffee' ])
  .pipe(findDependencies())
  .pipe(coffee())
  # ...

The problem is that the gulp.src call can finish and emit an end event before the recursion from findDependencies finishes, resulting in a Error: write after end exception.

In principle, I'm trying to take a single file, and mid-pipeline, expand that to more files, and emit those down the stream (from that mid-pipeline point on) in certain order.