Сергей Соколов

document.body.innerHTML += '<b>' + k + '</b> ' + this[k] + '<b>';

• <b> – делает текст жирным;
  
• <br> – разрыв строки, далее пойдёт с новой строки.
  

{
  const a = Math.random();
  const b = a > 0.5;
  b  ||  console.log(a, 'меньше');
  b  &&  console.log(a, 'больше');
}

The returned array also exposes a columns property containing the column names in input order (in contrast to Object.keys, whose iteration order is arbitrary).

var a = [11,22];
a.columns = [333, 444];

JSON.stringify(a)
> "[11,22]"

JSON.stringify(a.columns)
"[333,444]"

A global environment record is logically a single record but it is specified as a composite encapsulating an object environment record and a declarative environment record. The object environment record has as its base object the global object of the associated Realm. This global object is the value returned by the global environment record’s GetThisBinding concrete method. The object environment record component of a global environment record contains the bindings for all built-in globals (clause 18) and all bindings introduced by a FunctionDeclaration, GeneratorDeclaration, or VariableStatement contained in global code.
The bindings for all other ECMAScript declarations in global code are contained in the declarative environment record component of the global environment record.

* @params {String} [separator=' '] string to separate number groups
* @params {String} [group_length=3] number group length
* @params {String} [suffix=''] suffix to append to number

var comma_separator_number_step = $.animateNumber.numberStepFactories.separator(' ', 3, ' руб.');

let out = "";
for (let i = 0, prev = ""; i < str.length; i++) {
  const c = str.charAt(i);
  if (c === prev  &&  c >= "0"  &&  c <= "9") continue;
  out += (prev = c);
}

arr.reduce((acc, c) => acc.concat(...c.items.filter(e => [9,10].indexOf(e.id) > -1)), [])

Ограничения на имена свойств

Мы можем использовать только строки и символы в качестве ключей свойств. Все другие типы данных будут автоматически преобразованы к строке.

Например, если использовать как ключ число 0, то оно превратится в строку "0"

{
  const el1 = document.getElementById("block_1");

  // второй div, предположу, пока не присутствует в разметке
  // поэтому его надо создать:
  const el2 = document.createElement("div");
  el2.id = "block_2";
  el2.innerText = "content 2";

  // собственно, замена:
  setTimeout(() => el1.parent.replaceChild(el2, el1), 3e3);
  
  // или то же более современно, не работает в IE:
  setTimeout(() => el1.replaceWith(el2), 3e3);
}

const data = {};

let us={id:124,room:10,string:"1_2_3_4_5_6_7_8_9_10-1"};
data[us.id] = [us.room,us.id,Nnum,bet];

const data = new Map();
data.set(us.id, [us.room,us.id,Nnum,bet]);

let timerTab =[];
timerTab.push([10,new Date().getTime()+6000]);
timerTab.push([11,new Date().getTime()+9000]);

setInterval(function () {
    const now = Date.now();
    timerTab = timerTab.filter(function (timer) {
        if (timer[1] <= now) {
            console.info("Таймер истек", timer[0]);
            return false; // не войдет в выбранные
        } else {
            console.info(`${timer[0]}: ${timer[1] - now}`);
            return true; // войдет в выбранные
        }
    })
}, 1000)

this.configDb = (({ user, password, connectString }) => ({ user, password, connectString }))(c);

var c = {
      user: "User",
      password: "Password",
      connectString: "Connect String",
    };
var configDb = (({ user, password, connectString }) => ({ user, password, connectString }))(c);

console.log(configDb)
// Object { user: "User", password: "Password", connectString: "Connect String" }

const headerNavMenu = document.querySelector('.headerNav > ul');

const menuToggle = () => {
  const value = headerNavMenu.style.display;
  headerNavMenu.style.display = (value == 'none' || value == '') ? 'flex' : 'none';
}  

[...document.querySelectorAll('.mobileButton, .closeMobileMenu, .headerNav > ul > li')]
.forEach(el => el.addEvenetListener('click', menuToggle));