I like FP too, but most languages, including FP ones, have both mutable/immutable references and mutable/immutable values. And in JS, things like strings, numbe

I like FP too, but most languages, including FP ones, have both mutable/immutable references and mutable/immutable values. And in JS, things like strings, numbers and booleans are immutable value, plus immutable.js is quite popular for immutable data structures, especially in React+Redux apps.