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javascript snippets interview questions set 1

 

javascript snippets interview questions set 1

Hey, I have just started a new set for javascript snippets interview questions which will make your understanding of javascript more clear.It's more like testing your knowledge and then clearing things that you have doubt or if you have heard for the first time about it.

So let's begin with testing and improving yourself,

Q1. Which operator returns true if the two compared values are not equal?

 a)<>

 b)~

 c)==!

 d)!==



Q2. How is a forEach statement different from a for a statement?

 a)Only a for statement uses a callback function.

 b)A for statement is generic, but a forEach statement can be used only with an array.

 c)Only a forEach statement lets you specify your own iterator.

 d)A forEach statement is generic, but a for statement can be used only with an array.



Q3. Which statement creates a new object using the Person constructor?

 a)var student = new Person();

 b)var student = construct Person;

 c)var student = Person();

 d)var student = construct Person();



Q4. When would the final statement in the code shown be logged to the console?

let modal = document.querySelector('#result');

setTimeout(function(){

    modal.classList.remove('hidden);

}, 10000);

console.log('Results shown');

 a)after 10 second

 b)after results are received from the HTTP request

 c)after 10000 seconds

 d)immediately



Q5. You've written the code shown to log a set of consecutive values, but it instead results 

in the value 5, 5, 5, and 5 being logged to the console.

Which revised version of the code would result in the value 1, 2, 3 and 4 being logged?

 for (var i=1; i<=4; i++){

    setTimeout(function(){

        console.log(i);

    }, i*10000);

   }

a) for (var i=1; i<=4; i++){ (function(i){ setTimeout(function(){ console.log(j); }, j*1000); })(j) }


b) while (var i=1; i<=4; i++) { setTimeout(function() { console.log(i); }, i*1000); }


c) for (var i=1; i<=4; i++) { (function(j) { setTimeout(function(){ console.log(j); }, j*1000); })(i) }


d) for (var j=1; j<=4; j++) { setTimeout(function() { console.log(j); }, j*1000); }



Q6. What is the result in the console of running this code?

"use strict";

function logThis() {

    this.desc = "logger";

    console.log(this);

}

new logThis();

a) undefined

b) window

c) {desc: "logger"}

d) function


I hope you like the article. Please stay connected for more such articles.

Please check the comment sections for answers and if any doubts let me know there. 


You can also follow me on Twitter or Linkedin for the latest updates.

Written By:

Saurabh Joshi

Comments

  1. 1) Explanation:
    !== not equal value or not equal type
    var x = 5,
    x !== 5 false
    x !== "5"true
    x !== 8 true

    ReplyDelete
  2. 6)Explanation:
    When you call a function with new keyword,
    JavaScript creates a new empty object. If ‘this’ keyword is used within that function, it refers to the newly created empty object.
    If you’re not explicitly returning any object,
    JavaScript would return that newly created object/

    ReplyDelete
  3. I think Q5.c has typo. it should be ( , instead of { before fitst function for IIFE

    ReplyDelete

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