interview questions

by Krishna Ananthi

JavaScript

let users=[{id:1,name:"Rani",isActive:true},{id:2,name:"anu",isActive:true},{id:3,name:"adhi",isActive:false}];

users.sort((u1,u2)=>u1.age>u2.age? 1:-1)
let userName = users.filter(user=>user.isActive).map(user=>user.name);

console.log(userName);

//console.log(foo);
foo=11;

//closure - counter func

function counter(){
		let count = 0;
    return  {
     							increment:()=>{
                  		count++;
                  },
                  getValue:()=>{
                  return count;
                  }
    }
}

let curCounter = counter();
console.log(curCounter.getValue())
 curCounter.increment();
console.log(curCounter.getValue())
 curCounter.increment();
console.log(curCounter.getValue())
 curCounter.increment();
console.log(curCounter.getValue());
console.log(curCounter);

// multiply(1)(2);

function multiply(a){
				return (b)=> {
        			return a*b
        }
}
console.log(multiply(3)(4))
//simplified version

const multiply1 = n1 => n2 => n1*n2;
console.log(multiply1(3)(4));


//push obj to array
function insert(arr,newEle){
return [...arr, newEle]
}

console.log(insert([1,2,3],8))

//concat 2 array
function merge(arr,arr2){
return [...arr, ...arr2]
}

console.log(merge([1,2,3],[4,5,6]))