fwon

function deepClone(obj, hash = new Map()) {
    if (Object(obj) !== obj) return obj; // primitives
    if (hash.has(obj)) return hash.get(obj); // cyclic reference
    var result = Array.isArray(obj) ? []
               : obj.constructor ? new obj.constructor() : {};
    hash.set(obj, result);
    if (obj instanceof Map)
        Array.from(obj, ([key, val]) => result.set(key, deepClone(val, hash)) );
    return Object.assign(result, ...Object.keys(obj).map (
        key => ({ [key]: deepClone(obj[key], hash) }) ));

fwon

function getByteLen(normal_val) {
    // Force string type
    normal_val = String(normal_val);

    var byteLen = 0;
    for (var i = 0; i < normal_val.length; i++) {
        var c = normal_val.charCodeAt(i);
        byteLen += c < (1 <<  7) ? 1 :
                   c < (1 << 11) ? 2 :
                   c < (1 << 16) ? 3 :

fwon

// reducer
function todosReducer(state, action) {
  switch (action.type) {
    case 'add':
      return [...state, {
        text: action.text,
        completed: false
      }];
    // ... other actions ...
    default: