Check for broken implementation of `Uint8Array.prototype.toHex`

[brc-dd]

Not sure if v8 staging features are covered, but when using deno run --v8-flags=--js-base-64 or node --js-base-64 or chrome://flags/#enable-javascript-harmony, the following code gives wrong output:

// foo.ts, run with:
// deno run --v8-flags=--js-base-64 foo.ts

import 'https://deno.land/x/corejs@v3.43.0/index.js'

console.log(new Uint8Array(8).fill(255).toHex()) // gives VfVfVfVfVfVfVfVf

Solution can be adding a check similar to:

core-js/packages/core-js/modules/esnext.uint8-array.set-from-base64.js

Lines 9 to 16 in e002f78

	var INCORRECT_BEHAVIOR_OR_DOESNT_EXISTS = !Uint8Array || !Uint8Array.prototype.setFromBase64 || !(function () {
	var target = new Uint8Array([255, 255, 255, 255, 255]);
	try {
	target.setFromBase64('MjYyZg===');
	} catch (error) {
	return target[0] === 50 && target[1] === 54 && target[2] === 50 && target[3] === 255 && target[4] === 255;
	}
	})();

From denoland/deno#25051 (comment)

[zloirock]

Thanks for the note. Feel free to add a PR -)

[brc-dd]

Created #1440.

There are other issues as well, but not sure if they need fixing.

---

  assert.throws(() => fromBase64('SGVsbG8gV29ybGQ1=', null), TypeError, 'incorrect options argument #1');
  assert.throws(() => fromBase64('SGVsbG8gV29ybGQ1=', 1), TypeError, 'incorrect options argument #2');

^in v8 implementation, these throw:

Uncaught SyntaxError: Found a character that cannot be part of a valid base64 string.

The SyntaxError itself is correct (because of wrong padding), but seems like v8 ignores malformed options.

---

  assert.throws(() => array.toBase64(null), TypeError, 'incorrect options argument #1');
  assert.throws(() => array.toBase64(1), TypeError, 'incorrect options argument #2');

^these don't throw anything.

---

I'll probably report these on the Chromium issue.

[zloirock]

@brc-dd I think that those cases also should be fixed.

[brc-dd]

In those cases should we replace the whole implementation (like similar to above PR) or is it possible to validate the options and then call the builtin functions?

[zloirock]

Since it's flagged, I think it's fine just to replace them - I hope that it will be fixed when it will be shipped.