When entry file has a shebang, output it in the first line of the bundle

🙋 feature request

In UNIX systems, the first line of a script can be a shebang with the path to the interpreter. When the main entry file has this shebang (and optionally when target: node), this shebang line could be taken out of the bundled modules and outputted in the first line of the bundle.

🤔 Expected Behavior

hello-world.js:

#!/usr/bin/env node

console.log("Hello, world!");

$ parcel build -t node hello-world.js

dist/hello-world.js:

#!/usr/bin/env node

// parcel bundle prologue ...function(require,module,exports) {
console.log("Hello, world!");
// }... parcel bundle epilogue

😯 Current Behavior

dist/hello-world.js:

// parcel bundle prologue ...function(require,module,exports) {
#!/usr/bin/env node
console.log("Hello, world!");
// }... parcel bundle epilogue

(which is actually a SyntaxError)

🔦 Context

I run into this when trying to make executable scripts for node which have all their files already bundled.

[mischnic]

You need to make sure Parcel knows that you’re build for a Node target, not for the browser. The easiest way to achieve that is adding

  "engines": {
    "node": ">=10"
  }

to your package.json

[cprecioso]

@sintloer That’s great, I’ll start using it! Maybe you could copy the shebang of the entry file instead of having to define it in the package.json?

However, I still think parcel should have native support for this, especially as the input is a valid node script but the output is as SyntaxError.