//1
let a1 = () => alert('Привет')

//2

let b1 = (b) => b = b ** 3

//3

let c1 = (a, b) => (a + b) / 2

//4

let d1 = (a = 0, b = 0, c = 0) => g = a + b + c

//5

let e1 = (a, b) => {
    if (b === undefined) {
        z = Math.round(Math.random()*a) 
    } else {
        z =   ((Math.round(Math.random() * (b - a))+a))
    }
      return z
}

//6
let p = ""
let f1 = (...arguments) => {
    
    for (i = 0; i < arguments.length; i++){
        p = p + "," + arguments[i] 
        
    }
    
    alert(`Hello ${p}`)
}

//7
let sum1 = 0
let g1 = (...arguments) => {
    for (i = 0; i < arguments.length; i++){
        sum1 += arguments[i]
    }
    return sum1
}


//sort

var persons = [
    {name: "Иван", age: 17},
    {name: "Мария", age: 35},
    {name: "Алексей", age: 73},
    {name: "Яков", age: 12},
]


function sort1(array, key, bool = true) {
     
    if (bool) {
        array.sort((a, b) => a[key] > b[key] ? 1 : -1)
    }
    else {
        array.sort((a, b) => a[key] < b[key] ? 1 : -1)
        return console.log(array)
    }
}   

//sort(persons, "age"); //сортирует по возрасту по возрастанию
sort1(persons, "name", false); //сортирует по имени по убыванию

//array map

["1", {}, null, undefined, "500", 700].map(x => typeof(x) === 'string' ? parseInt(x) : x)

//array reduce
    
["0", 5, 3, "string", null].reduce(f)

function f(a, b) {


    if (typeof (a) === 'number' ) {
        a = a
    } else {
        a = 1
    }
    if (typeof (b) === 'number') {
        b = b
    } else {
        b = 1
    }
    return a * b

}

//object filter

var phone = {
    brand: "meizu",
    model: "m2",
    ram: 2,
    color: "black",
};

function filter(object , search ,value) {
    for (let key in object) {
        if (key != search & object[key] != value)
            delete object[key];

           
        }
        return phone
}

filter(phone, "color", 2)

//object map ????????

function map(obj, funct){
    for(key in obj){
        funct(obj, key, obj[key]);
        delete obj[key];
    }
    return obj;
}

function by(obj, key, value){
    obj[key + "_"] = value + "$";
    return obj;
}
console.log(map({ name: "Иван", age: 18, tel: 16780 }, by))


//Sum

function sum(a){
    if (a === 1){
        return a
    }
    else {
        return a + sum(a - 1)
    }

    
}