// ES6
let a = () => alert("Hello");
let cube = (x) => x**3;
let avg2 = (a,b) => (a+b)/2;
let sum3 = (a,b,c) => (a+b+c) || (a+b);
let intRandom = (a,b) => {  if(b === undefined){
    c = (Math.round(Math.random() *a))
   } else 
   c = (Math.round(Math.random() * (b - a) + a));
return c    
};
let greetAll = (...params) =>{
    let guys = '';
    for(i = 0;i<params.length;i++){
        guys+=  "," +  " " + params[i]
    }
    alert(`Hi ${guys}`)
        
};
let sum = (...params) =>{
    let result = 0;
    for(i = 0;i<params.length;i++){
  result += params[i]};
return result
};



// array map

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

// array reduce

let arr1 = ["0", 5, 3, "string", null]
arr1.reduce( (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

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

let objFilter = (object,keys,value) => {
    for(let key in object){
        if(key != keys  && object[key] !=value)  
        delete object[key];
    }
    return object
}