Positional binding after rest binding?

💡 Ideas
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Related: rest end only but not rest start only?

I also recall this being discussed on the old es-discuss mailing list, but dredging through that isn't something I feel like doing.

I'd like to see stuff like (a, ...bs, c) => ... be possible. To name a few examples of use case and precedent:

  • Node's callback idiom the whole time has been f(...args, callback), and any function forwarding all but the callback needs to have such a prototype.
  • GitHub - scijs/ndarray: 📈 Multidimensional arrays for JavaScript has an ndarray.set(...indices, value).
  • CoffeeScript supported this since before ES6. ES6 got its very rest parameter idea in part from it, so it's pretty strong precedent. I think Babel and/or Traceur also once supported it as an extension way back then.

There's of course a lot more, and I could probably spend hours just finding and adding precedent here.

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I also found this, and I'm not sure why it didn't show up in my search results: Inverse Rest Operator

This is a near dupe of that, just a little more detailed.