Parcel: Do not include the parcelRequire helper if not necessary

[kirly-af]

❔ Question

Is it possible to avoid the addition of the parcelRequire helper in the case of a JS bundle which does not use require or any sort of module feature in the target script?

🔦 Context

I pass a simple script to parcel which does not use any require or import and I'd like to reduce the overhead produced by parcel.

💻 Code Sample

🌍 Your Environment

| Software | Version(s) |
| ---------------- | ---------- |
| Parcel |1.11.0
| Node |8.11.3
| Yarn | 1.13.0
| Operating System |

[mischnic]

You could use --experimental-scope-hoisting.

[mischnic]

(This is quite hard to implement in the current pipeline)

[jiraiya972]

related to #2451

[kirly-af]

@mischnic As seen in #2451, the real problem that I have is the "Mismatched anonymous define()" error. Would it be that difficult to handle? What's your take on this @devongovett?

[jhpratt]

@mischnic How reliable is that flag? It certainly looks to work on trivial cases.

[mischnic]

How reliable is that flag? It certainly looks to work on trivial cases.

It even works in most complex cases 😄. I'd say it's quite reliable now, there are only some edge cases left. Please try it and open an issue if you find one!

[kirly-af]

@mischnic As the flag is "experimental", any idea when this should be ready for production?

[jhpratt]

@devongovett Should this really be closed? An experimental flag is not the same as being completed.

[soophie]

The flag didn't work for me. For test purposes I only have one script file with a console.log() included at the end of my HTML file. So there is definitely no reason for parcelRequire() here.

This is my build task:

"build": "parcel build index.html --out-dir build --no-minify --no-source-maps --experimental-scope-hoisting",

[JakubKoralewski]

If someone could explain to me, if I have a single js file - why do I need to require anything inside the js file (parcelRequire) if it's all inside that file? i.e. what is parcelRequire actually for?

[mischnic]

why do I need

It isn't needed, but the current approach is: take the wrapper and insert all JS modules. The unfortunate side-effect of this simplification is that a single JS module also has the wrapper code.

[kaushik-evani]

@jhpratt I agree. Can we keep this open?

[mischnic]

For Parcel 2, scope hoisting (which has no such wrapper) enabled by default in production builds. So I would say this is already somewhat fixed.