On 10/28/17, Frederick Stark <coagm...@gmail.com> wrote: > I'd just like to thank TC39 for not breaking compatibility. All the niche > old libraries I use that were written in ES5 still work in my ES6+ projects > with no issues.
introducing the new typeof Symbol() === 'symbol' does break backwards compatibility with many es5 libraries that default to 'object' type if typeof is not 'boolean', 'number', 'string', 'function', or 'undefined'. fortunately symbols are not used by everyday programmers (and rightly so), so its rarely encountered by these libraries. if tc39 did really care about backwards-compat, they should've treated it as an 'object' type with a Symbol.isSymbol subtype-check like Array.isArray. this brings up another backwards-compat issue - what's the typeof for proposed BigInt / Int64 / Decimal? i prefer treating them as 'number' or 'object' with subtype-checks BigInt.isBigInt et al., but Symbol has dangerously broken that precedent. in general my opinion is tc39 should freeze the existing set of typeofs (and use subtype-checks) for sake of backwards-compat and library/tooling stability. _______________________________________________ es-discuss mailing list es-discuss@mozilla.org https://mail.mozilla.org/listinfo/es-discuss
