plugin transformer does not support async functions

[Pyrolistical]

• node 8+

Steps to reproduce

function plugin() {
  return async function transformer(tree) {
    tree.children = await somethingAsync()
    return tree
  }
}

Expected behaviour

Expect to be the same as

function plugin() {
  return function transformer(tree) {
    return somethingAsync()
      .then((result) => {
        tree.children = result
        return tree
      })
  }
}

Actual behaviour

The plugin is skipped.

Root cause

serapath/x-is-function#1

[wooorm]

Oh that sucks! Thanks for the write up. I’m fine with inlining the function with a fix here!
Or: maybe replace all func(x) checks with typeof x === 'function', would the tests still pass when we do that?

[Pyrolistical]

ya, i don't know why typeof x === 'function' wasn't used in the first place

[wooorm]

Because regexes are classified as functions in some browsers, but I think we can ignore that now.