Possibly broken in IE11

I noticed that JSBI is broken in a test application when running in IE11.

When I exclude JSBI in webpacks babel-loader exclude (jsbi is parsed like the rest of my code):

This possibly points to:

if (!_(t) || i(t) !== t) throw new RangeError("The number " + t + " cannot be converted to BigInt because it is not an integer");

I use core-js@3 and regenerator-runtime as polyfills. Maybe I need something else as well?

When I do not exlude JSBI and treat it like any other dependency (jsbi is included in babel-loader): This time it is unfortunately absolutely impossible to tell what upsets poor IE. Maybe its the same statement, who knows 🤷‍♂️.

Is the UMD version tested? Works fine in Firefox 80, but not in IE11.

I also noticed https://github.com/GoogleChromeLabs/jsbi/issues/42. I tested importing the common-js and mjs versions directly, however I still get similar results. IE is broken while Firefox works.

[glr0221]

I just wanted to say, I have successfully used JSBI with IE. Thank you so much @jakobkummerow @mathiasbynens @Miladiir

[jakobkummerow]

Looks like IE11 doesn’t support Math.imul and Math.clz32, which JSBI uses. At least, that’s the result I get when I comment out “minify()” in rollup.config.js, regenerate the UMD version, and test var a = JSBI.BigInt('12345678901234567890') with that on an IE11 VM.

As a short-term workaround, you can provide a very simple polyfill (which does not have the proper semantics, but is good enough for JSBI):

if (!Math.imul) {
  Math.imul = function(a, b) {
    return ((a & 0xFFFF) * (b & 0xFFFF)) | 0;
  }
}
if (!Math.clz32) {
  Math.clz32 = function(x) {
    if (x === 0) return 32;
    return 31 - (Math.log(x >>> 0) / Math.LN2 | 0) | 0;
  }
}

If you’re worried about breaking other modules that might want to use these functions, you can find functionally fully correct polyfills on MDN.

I know next to nothing about Babel. Presumably it has a way to polyfill Math functions, but I don’t know how to make it do that.