Legal comments

Preserving or relocating license banners and headers.

A legal comment is a banner a rewriter must not silently delete - /*! … */ headers, //! … comments and similar markers.

legalComments controls what happens to them:

Value	Behaviour
`default`	Resolved to `endOfFile` when bundling, `inline` otherwise.
`none`	Drop the banners. Only legal when the licence allows it.
`inline`	Keep each banner next to the code it covers.
`endOfFile`	Collect every banner and emit them once at the top of the output.
`linked`	Put the text in a `<name>.LEGAL.txt` file and leave a pointer comment.
`external`	Write the `<name>.LEGAL.txt` files with no pointer comment.

guchho build src/app.js --bundle --outdir=dist

linked and external need an output directory, because a .LEGAL.txt file has to be written somewhere.

Banners and footers

For text you want to add rather than preserve, use banner and footer. Both are maps from file kind to text:

build: {
  banner: { js: '/*! (c) 2026 CodeHemu - MIT */' },
  footer: { css: '/* generated by Guchho */' },
}

The same text is available per call through TransformOptions.banner and TransformOptions.footer.