modd-js

A simple immutablity utility, simplifies functional changes for react, redux, and other config modification.

import {Modd, Apply, types} from 'modd';
let {Str, Arr, Map} = Modd.types;
// for type completion and Arr has _ as utility
let M = Modd({
    user: {
        uname: Str,
        upw: Str,
    },
    pets: Arr({pname: Str})
});
// a caveat that you cannot use keys like "name" as key for functions.
let state = {
    user: {
        uname: 'my-old-name',
        upw: 'new-pw'
    },
    pets: []
};
let newState = Apply(state)([
    M.user.uname('new-name'), // {user: {uname: 'new-name', ...}, pets: ...}
    M.user.uname(s => s.toUpperCase()) // {user: {uname: 'NEW-NAME', ...}, ...},
    M.pets._(0).pname('fred') // {user: {...}, pets: [{pname: 'fred'}]}
]);