Rename toArray to arrayFromSet and simplify export syntax

[benjamn]

As @alessbell has reported in codesandbox/sandpack#940, it appears Sandpack may have a transpiler bug when compiling the following code:

export const {
  from: toArray = (collection: Set<any>) => {
    const array: any[] = [];
    collection.forEach(item => array.push(item));
    return array;
  },
} = Array;

It's understandable the combination of export, destructuring, renaming from: toArray, and a default expression would be unusual enough to have escaped testing, but this works with other transpilers, and is valid TypeScript (and should compile to equivalent valid JS).

What happens, specifically, is that exports.toArray never gets assigned like exports.hasOwnProperty and exports.maybeUnsubscribe, presumably because toArray is not detected as an exported identifier.

Fortunately, there's another way of writing this code that should be less challenging to transpile:

export const arrayFromSet: <T>(set: Set<T>) => T[] =
  Array.from ||
  function (set) {
    const array: any[] = [];
    set.forEach(item => array.push(item));
    return array;
  };

I took this opportunity to rename the helper function from toArray to arrayFromSet, reflecting the fact that we use this function only for converting sets to arrays, which allows us to keep the fallback function simple (for use when Array.from is not available).

[alessbell]

Thanks! 🎉