Check for broken implementation of Uint8Array.prototype.toHex

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)

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

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.

@brc-dd

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

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?

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.

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Check for broken implementation of `Uint8Array.prototype.toHex` #1439

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	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;
	}
	})();

Check for broken implementation of Uint8Array.prototype.toHex #1439

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zloirock commented on Jun 28, 2025

brc-dd commented on Jun 29, 2025

zloirock commented on Jun 29, 2025

brc-dd commented on Jun 29, 2025

zloirock commented on Jun 29, 2025

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Check for broken implementation of `Uint8Array.prototype.toHex` #1439