api question/suggestion for Immutable.from()

[raould]

Premature optimization suggestion, the idea being to avoid merge() calls if possible. See the Clojure transients stuff I think off the top of my head for similar thoughts on using mutation for efficiency inside an otherwise immutable world.

(1) basic

Immutable.from({foo:1},{bar:2}); // returns {foo:1,bar:2}.
Immutable.from({foo:1},{foo:2}); // returns {foo:2}.

(2) more bonus, pesudocode:

Immtuable.from({foo:1,bar:2},(e)=>{e.foo=()=>42}); // returns {foo:42,bar:2}.