Unroll the Rollup banner !

Recently when creating multiple bundles for OpenJSCAD using rollup we needed to add a shebang to the output command line bundle to enable running it as a script.

We went through multiple iterations before finding, "lo and behold!" a setting in rollup itself.

Solution:

You can specify a banner option : it is a string that will appear at the very top of your output bundle: very handy for creating cli tools!

{
  banner: '#!/usr/bin/env node\n',
  //other settings here
}

Other (not so great) solution: using the rollup-plugin-post-replace plugin:

you need to add a replace entry to the plugins list :

This relies on the fact that use strict is added to the top of the bundles (when transpiling es6)

{
  plugins: [
    replace({
      "'use strict';": "#!/usr/bin/env node\n'use strict';"
    })
   ]
}

the problem with this , is that it utterly fails if you have more than one use strict entries ...