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JavaScript Practice Questions - Part 1 

Prashant Surya  |   Feb 28, 2020  |  Views: 316
pictures

Description:

What will be the outputs of the following questions ?


Question 1:


var output = (function(x) {
  delete x;
  return x;
})(0);
console.log(output);

//0


Question 2:


var Employee = {
  company: 'xyz'
}
var emp1 = Object.create(Employee);
delete emp1.company
console.log(emp1.company);

//xyz


Question 3:


0.1 + 0.2 === 0.3
//false


Question 4:


console.log(0.1 + 0.2);
console.log(0.1 + 0.2 == 0.3);


0.30000000000000004
false


Question 5:


console.log(1 +  "2" + "2");
console.log(1 +  +"2" + "2");
console.log(1 +  -"1" + "2");
console.log(+"1" +  "1" + "2");
console.log( "A" - "B" + "2");
console.log( "A" - "B" + 2);


"122"
"32"
"02"
"112"
"NaN2"
NaN


Question 6:

for (var i = 0; i < 5; i++) {
setTimeout(function() { console.log(i); }, i * 1000 );
}

5, 5, 5, 5, 5



Question 7:


console.log("0 || 1 = "+(0 || 1));
console.log("1 || 2 = "+(1 || 2));
console.log("0 && 1 = "+(0 && 1));
console.log("1 && 2 = "+(1 && 2));


0 || 1 = 1
1 || 2 = 1
0 && 1 = 0
1 && 2 = 2



Question 8:

console.log(false == '0')
console.log(false === '0')

true
false



Question 9:


var a={},
    b={key:'b'},
    c={key:'c'};
a[b]=123;
a[c]=456;
console.log(a[b]);

456



Question 10:


console.log((function f(n){return ((n > 1) ? n * f(n-1) : n)})(10));


3628800

Comments:
Content Contributor
Prashant Surya

Prashant Surya

Software developer at Uniserve Data Technologies Pvt. Ltd.  |   Noida, Uttar Pradesh, India

I am a software developer, freelancer and trainer working on technologies likes. MEAN stack, MERN Stack, ASP.NET full stack, WebRTC, socket.io ,PWA, SQL, JavaScript, jQuery, HTML, CSS, SEO, responsive UI/UX designing... having 7 years of experience in development in multiple domains like, eCommerce, RTA, capital markets, education, real estate...


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