qetr1ck-op

'use strict';

function str(strings, ...values) {
  let str = "";

  values.forEach((val, i) => {
    str += strings[i];
    str += values[i];
  })

qetr1ck-op

const counter = (state = 0, action) => {
    switch (action.type) {
        case 'INCREMENT':
            return state + 1;
        case 'DECREMENT':
            return state - 1;
        default:
            return state;
    }
}

qetr1ck-op

const addCounter = (list, 0) => {
    //return list.concat([0]);
    return [...list, 0];
};

qetr1ck-op

const removeCounter = (list, i) => {
    /*return list.slice(0, i)
        .concat(list.slice(i + 1))*/
    return [
        ...list.slice(0, i),
        ...list.slice(i + 1)
    ];
}

qetr1ck-op

const incrementCounter = (list, i) => {
    /*return list.slice(0, i)
        .concat(list[i] + 1)
        .concat(list.slice(i + 1));*/

    return [
        ...list.slice(0, i),
        list[i] + 1,
        ...list.slice(i + 1)
    ]

qetr1ck-op

const testAddCounter = () => {
  const listBefore = [];
  const listAfter = [0];

  deepFreeze(listBefore);

  expect(
    addCounter(listBefore)
  ).toEqual(listAfter);
};

qetr1ck-op

const toggleTodo = (todo) => {
    /*mutated version
    todo.completed = !todo.completed;
    return todo;*/

    /*Object.assing version
    return Object.assign({}, todo, {
        completed: !todo.completed
    });*/

qetr1ck-op

Object.defineProperty(obj, prop, descriptor)

qetr1ck-op

const o1 = {
  prop: 'prop'
}

const o2 = Object.setPrototypeOf({
  prop2: 'prop2'
}, o1);

console.log(o2.prop2, o2.prop)

qetr1ck-op

function multiple(a, b) {
    return a * b;
}

function square(n) {
    return multiple(n, n);
}

function printSquare(n) {
    console.log(square(n));