Comment by zarzavat
In that case JS is not colored either because an async function is simply a normal function that returns a Promise.
As far as I understand, coloring refers to async and sync functions having the same calling syntax and interface, I.e.
b = readFileAsync(p)
b = readFileSync(p)
b = await readFileAsync(p)
readFileAsync(p).then(b => ...)
b = readFileSync(b)
If you have to call async functions with a different syntax or interface, then it's colored.
> In that case JS is not colored either because an async function is simply a normal function that returns a Promise.
Exactly, IMHO at least, JS doesn't suffer from the coloring problem because you can call async functions from sync functions (because the JS Promise machinery allows to fall back to completion callbacks instead of using await). It's the 'virality' of await which causes the coloring problem, but in JS you can freely mix await and completion callbacks for async operations).