btoa() and atob()

[silverwind]

All major browsers expose the btoa and atob globals for encoding ASCII strings as base64 and vice versa. It'd be beneficial for the "isomorphic" javascript topic if we'd provide these too:

• https://developer.mozilla.org/en-US/docs/Web/API/WindowBase64/btoa
• https://developer.mozilla.org/en-US/docs/Web/API/WindowBase64/atob

As for the implementation, we can't Buffer('string').toString('base64') because that would encode unicode while atob and btoa must per spec throw on charcodes > 255. https://github.com/mathiasbynens/base64 looks like a solid implemenation we could pretty much drop in.

[MylesBorins]

I'd be up for writing a bunch of tests if people want to see this happen

[jasnell]

While I understand the desire on this, it could just as easily be implemented as a userland module that registers the globals. I'm -0 on adding it in to core.

[mscdex]

I think I'm -1 on this for the same reason.

[trevnorris]

function btoa(str) {
  if (Buffer.byteLength(str) !== str.length)
    throw new Error('bad string!');
  return Buffer(str, 'binary').toString('base64');
}

Think that will about cover it.

Update: actually, that's a bad length check and I'm too tired to work the correct one. we'd probably have to expose v8::String::ContainsOnlyOneByte() for the fastest option.

[Fishrock123]

I'd rather not add more globals, ever if possible.

[tflanagan]

The fact that you are linking to a userland package that already gets over a 1000 downloads a week (via npm) is solid evidence that the need for this, in core at least, is very minimal

[silverwind]

By the way: Why doesn't v8 provide functions like these?

[bnoordhuis]

They're browser extensions, they're not part of the ECMAScript spec: https://html.spec.whatwg.org/multipage/webappapis.html#atob

[jasnell]

Feel free to continue discussing, but given the -1's, I'm closing.