Incorrect minification with a bigint value created by a binary operator inside conditions

[sapphi-red]

For input

export function foo(a, b) {
  if ((a | b) === 0) {
    throw new Error()
  }
}

esbuild outputs

export function foo(o,r){if(!(o|r))throw new Error}

But this changes the behavior when foo(0n, 0n) is called.
No error happens before minification, but an error happens after minification.

[evanw]

Thanks for the report. I assume this assumption was left over from before the introduction of bigints. Will fix.

[evanw]

Looks like this affects Terser too (which you also discovered): terser/terser#1587. This currently happens for all bitwise operators in esbuild:

Before (esbuild)	After (esbuild)
if ((a | b) === 0) throw '|'	if (!(a | b)) throw "|"
if ((a & b) === 0) throw '&'	if (!(a & b)) throw "&"
if ((a ^ b) === 0) throw '^'	if (!(a ^ b)) throw "^"
if ((a << b) === 0) throw '<<'	if (!(a << b)) throw "<<"
if ((a >> b) === 0) throw '>>'	if (!(a >> b)) throw ">>"
if ((a >>> b) === 0) throw '>>>'	if (!(a >>> b)) throw ">>>"
if (~a === 0) throw '~'	if (!~a) throw "~"

It's mostly the same for Terser except Terser doesn't do it for the >>> operator, which is funnily enough the only operator for which this is actually safe to do (because >>> throws when used with bigints):

Before (Terser)	After (Terser)
if ((a | b) === 0) throw '|'	if (!(a | b)) throw "|"
if ((a & b) === 0) throw '&'	if (!(a & b)) throw "&"
if ((a ^ b) === 0) throw '^'	if (!(a ^ b)) throw "^"
if ((a << b) === 0) throw '<<'	if (!(a << b)) throw "<<"
if ((a >> b) === 0) throw '>>'	if (!(a >> b)) throw ">>"
if ((a >>> b) === 0) throw '>>>'	if (a >>> b == 0) throw ">>>"
if (~a === 0) throw '~'	if (0 == ~a) throw "~"

Edit: Although the conversion of ~a === 0 to ~a == 0 that Terser does here is also problematic: ~-1n === 0 is false but ~-1n == 0 is true.