Compare and contrast with HTML's number-parsing algorithm

[domenic]

I don't think HTML's number-parsing algorithm should be adapted wholesale; I think symmetry with Number.prototype.toString is a more important consideration. (And HTML assumes radix 10.) But in the past people have complained about e.g. mismatches between HTML's date-parsing and ES's date-parsing, so it'd be good to discuss the differences.

Reference:

• https://html.spec.whatwg.org/#rules-for-parsing-integers
• https://html.spec.whatwg.org/#rules-for-parsing-floating-point-number-values

Of note are leading plus signs and other mismatches already filed.

[mathiasbynens]

Related upstream issue: https://github.com/tc39/ecma262/issues/2119 (Not about parsing specifically, but in the same spirit.)