MDN publishes correct polyfills for ES5 Array functions like map, reduce and forEach. I think it's worth shipping those and using them now.
Ultimately though, wouldn't you want to use a js preprocessor that lets you write full spec ES6 and compiles down to ES4 or whatever your runtime target is? That's available today, and it doesn't confuse the meaning of class, fat arrow, variable scoping, etc.
Ultimately though, wouldn't you want to use a js preprocessor that lets you write full spec ES6 and compiles down to ES4 or whatever your runtime target is? That's available today, and it doesn't confuse the meaning of class, fat arrow, variable scoping, etc.