refactor: use object map instead of switch statement

[laquasicinque]

Changed from using a switch statement to using an object map, which might be (slightly) faster.

[thecrypticace]

I would definitely challenge the idea that an object map is faster than a switch. Compiler's often generate jump tables for switch statements with constant cases. Object maps require indirection through a hash table. The switch is almost certainly faster especially if this ends up being a hot code path.

[laquasicinque]

This is true, it definitely used to always be the case where object maps were faster for large switch statements not sure these days.

[yyx990803]

Pretty sure switch is faster because it's more optimizable for JS engines.