JavaScript Mock Interview | Online Interview Questions and Answers (Part 2) 

I'm convinced the more you pump out content the bigger your channel will get because you've been under-sub'd now for a long time. Keep up the great work!

This mock interview series are really useful and unique. Well done techsith. I really don't understand who dislikes this :|

I'm so excited about this series! Thanks to you and contributor!

I tried to write higher order functions like reduce myself. This is what I came up with: function myReduce(arr,cb){ let sum = 0; for(let i = 0; i < arr.length; i++){ sum = cb(sum,arr[i]); } return sum; } Then I call it like this: let sum = myReduce([1,2,3,4,5], (sum, el)=> { return sum + el; }) I also wrote filter and map functions in a similar way. Really helped me boost my overall understanding.

this man sparked my interest in coding....thanks al lot for such interesting content

I can totally relate to the interviewee. It is so easy to get out of practice with logic just working on frame works day to day which is why this video is so awesome..

Here's a cute trick to find the missing number in the array, and it doesn't even matter if the array is sorted. const arr = [1,2,3,4,6,7]; // 5 is missing const max = arr.length + 1; const reducer = (a,b) => a + b; const total1 = max * (max + 1) / 2; // Math trick! const total2 = arr.reduce(reducer); const missingNumber = total1 - total2; console.log(missingNumber); // Output will be 5

I love this series. Subscribed especially for these.

This is an absolute quality content.

Guy who is giving an Interview is very knowledgeable person

for the second question to get the missing number you have to return ary2[i]-1 instead of ary2[i] because if let us say 7 was missing then ary2[i] would be 8. Anyways the difference of sum part was genius!

Thank you for all your efforts in making this series and educating us :)

Nice question about owned coins 👍 , i think it's about greedy algorithms

For 1 number missing from 1...100 I thought the exact thing which @techsith suggested. The total sum of 1..100 and then subtracting it by presently available array and u have the answer. Great My mind is working now. Hopefully will be able to crack by the Coding round at PayTm now!

For missing number in array, you can just use includes method with a for loop... Its also simple

q3) find the missing number const missingNum = (arr) => { const len = arr.length+1; const sum= (len*(len+1))/2; // using sum of natural numbers formula const arrSum = arr.reduce((s,c)=> s+c,0); return sum-arrSum; }

Amazing series...please make more videos like these

const set = [...new Set(arr)]; //You know its 1-100 missing one number, and it works without sorting.// for (let i=1; i

the last task was simple for me, something like: let str = "i love javaScript"; str.split(' ').map(e => e.split('').reverse().join('')).reverse().join(' ');

The finding missing number in array. One possible solution is using indexOf condition in a loop and return value of index if get -1

thanks for this series. it helps every js developer.

i should have visited this beforehand. so much informative.

Thanks, my friend! You are the best teacher!

Trying to prep for my first ever technical interview and this series has been so valuable. Easily the best thing I've watched (in terms of gaining confidence and identifying gaps in my knowledge). Thank you! Would you consider bringing this series (or similar ones) back?

const ary = [1, 4, 7, 3, 6, 2, 5, 9]; const ary2 = ary.sort((a, b) => a - b); let len = ary2.length; let total = (len + 1) * (len + 2) / 2; let aryTotla = ary2.reduce((t, i) => (t + i)); console.log(ary2); console.log(total - aryTotla);

This series is really very helpful. Thanks .

For missing number taking exor will be the best approach

Please keep bringing out content like this! Great work

Question with the array, watched till 10:00. Pretty exiting series; var x = [1,2,3,4,5,7,8,9,10]; var y = x[0] + 1; for (let i = 0; i

I’m pretty sure that let or const even if assigned to a function will not get hoisted and the variable of the function will not initially be undefined, instead it will evaluated where is, almost positive all hoisting is avoided with those es6 keywords

find missing number alternative code: // making an array with all the numbers (not necessary if we simply loop with increments while checking let dummyArr = []; for (let i = 0; i < 10; i++) { dummyArr[i] = i + 1; } quesArr = [10, 2, 8, 4, 9, 6, 3, 5, 1]; // missing num is 7 let found; let quesStr = String(quesArr); // convert the question array into a string dummyArr.forEach((item) => { if (!quesStr.includes(String(item))) { found = item; } }); console.log(found);

I think in the solution to first problem where reduce method was used, there should be an initial value of accumulator to be passed as a second argument to the anonymous arrow function inside of the reduce method. ex: arr.reduce((acc, el) => { acc + el; }, 0);

20 years in front end and I wouldn't be able to even think of patterns for any of this, or the math operations. Never encountered any of it I guess.

mis= arr.length*(arr.length+1)/2 for (item of arr) mis-=item Console.log(mis)

Please do more of these videos. Subscribed :)

my answer for third question let obj = {} arr.map(item=>{ obj[item]=item; }) let res; for(let i=1;i

let sum =0 const arr = [1, 2, 5, 4,]; let n = arr.length+1; let totalS = n*(n+1)/2; for(var i = 0; i

For real: I clenched my fists while watching this and yelled "Return! You forgot 'return'!" making me look insane & stupid in front of my colleagues. Keep up the good work =)

const arr = [1,2,5,4,9,3,7,8,6,10,12]; missingNumber(arr); function missingNumber(arr) { arr.sort(function(a,b){return a - b}); for(var i=0; i< arr.length; i++) { if((arr[i] - i) > 1) { console.log("missing number is " + (i+1)); break; } } }

for problem at 12:00, ary.findIndex((a)=>a == undefined)

there is a small mistake. const len = ary.length + 1; because if a number is missing from the array, then if its added back to the array then the total number of elements will be increased by one hence the length will be increased by one.

38:13 _MY_ANSWER_ Another one :D // Function to reverse the given string const reverseString = (str) => { let reverseStr = str.split('').reverse().join(''); // We can also loop to reverse the string return reverseStr; } reverseString('Die hard JS Code'); //RESULT "edoC SJ drah eiD" Note: That Cashier problem is kinda tricky, so i ended up watching your solution for it. LOL :D

Yeah happy coz I also applied the same logic that you used to find the missing number. From an array😇

Lol my answer is weird but it works . I did let d = array[0] + array[1] + array[2] + array[3] console.log(d) ;

Var array=[1,2,7,6,4,5] For(let i=1;i=

I think the solution to the last question with str.split.reverse.join is less efficient because it actually runs for loop three times. Better solution in this case is: function reverseStr(str){ let reversed = "" for(let i = str.length-1; i >= 0 ; i--){ reversed += str.charAt(i); } return reversed; } It runs a for loop only once. Correct me if I missed something...

Thank you so much for this series!!

For one to hundred array question its pretty simple i think, just calulate the sum from one to hundred and then substract the sum of all the array elements.

Quite interesting idea... Thanks for this. Why not run the code and show the results for the viewers convenience?

25:22. leetcode 322, coin change. dp or dfs+memo

function missing(arr){ for(var i = 1; i < arr.length; i++){ if(arr[i] +1 != arr[i+1]){ return arr[i+1]-1; } } }

took me a few hours of thinking and rethinking the tiil / change logic but I knew I had to convert everything to pennies first, and know there was enough or not then move onto the next smaller denomination.

I think the second question should include a constraint that the number values aren't zero.

07:01 this is not work correctly when you call x(1,0); you need to check argument count with arguments.length property because 0 is falsy value and you can not use AND operator this way to check arguments count.

Missing number in array my solution let a = [ ], b; //array pushing for(let i = 1; i

function missing(arr){ for(var i=1;i

const ary = [8, 1, 10, 6, 2, 3, 7, 9, 4] //this is unordered array and one number is missing. find that missing number const sortedAry = ary.sort((a, b) => b - a) sortedAry.forEach((value, index, self) => { var diff = self[index - 1] - self[index]; if (diff >= 2) { console.log(value + 1) // 5 } })

Thanks techsith for these amazing series! It really helps to see what I am missing as a developer.

@19:20 I could the difference is : Function written within Line 2-4 is a Normal function, not supposed to be instantiated with new Keyword. Function written within Line 6-8 is a Constructor function, supposed to be instantiated with new Keyword. Please correct me If I'm mistaken differentiating that way.

You really great teacher.

Really exciting! (no sarcasm) Please, keep doing this =)

very useful.thank you

I was asked the coin problem in my interview too

Nice work

thank ts

thanks a lot, wait for more. do next one sooner please.

For the Missing no. problem at 17:01 , My solution -> console.log(arr.reduce((a,b)=>{ if(a-b!=0) return b-1; }));

MORE OF THIS!!!

function add(a, b) { return a && b ? a + b : function (c) { return a + c; } }; console.log(add(1,2)); //3 console.log(add(1)(2)); //3

TechSith Gaint i am pretty much confusion b/w webworkers vs websocket ... can you explain this topic and their difference please

Sir please make a video on type of UI questions that can be asked to a fresher in the interview.

8:21 _MY_ANSWER_ :D let arr = []; // Creating an array from 1-100 without a number in middle (here, it is 13) for(var i=100; i>=1; i--) { if(i === 13) {continue;} arr.push(i); } // Function to identify that missing number const showMissingNumber = (arr, limit) => { for(var i=1; i

Still people are asking those questions...hard to find these kind of videos...If he is associated with big brand then he will have at least double subscribers..

Hello sir m fresher now can you help me how I crack interview

Sir, I want to information about Webdavelapment, I have learned html5 css3 javascript bootstrap and angular so it required me to learn ajax and jquery kindly tell me I want to prepare to interview.

cool videos. please make more.

for(let i = 1; i

I have a question: in a real interview for a front-end position how many questions about HTML/CSS/frameworks should I expect to be asked? Do front-end interviews usually focus more on JS or on HTML/CSS/frameworks? Could you do a mock interview with some common HTML/CSS/framework questions? Thanks!

The coin problem solution in a horrible way :D const til = { penny: 12, nickel: 10, dime: 2, quarter: 12, dollar: 30 } //20.47 const coin_val = [0.01,0.05,0.1,0.25,1.00]; const get_coins = (amount, curr_coins, stage) => { if (amount { for (key in til){ til[key] = til[key] - change[key]; } } let change = get_coins(24.47, {}, 4); update_til(til, change); console.log("Change in minimum number of coins/notes is: ") console.log(change); console.log("Remaining coins/notes in the cash machine: ") console.log(til);

please start a javascript coding challenge series thanks in advance

The interviewee needs to learn how return statements work.

Bro do you think, getting a Web Developer job is possible without a degree (but with good skills) in India ?

at 19:46, is let function exp also hoisted? If var x= func () { } then only it'll be hoisted. Am I correct ?

15:02 this is completely false sir. array is sorted in descending order and loop index must start from zero and many more wrong things in here.???

What!! this is better. I did way better, I spell some words wrong and make some very simple syntax errors, and I was denied. I was thinking wow, people must be super good typer and super good coder who writes code without any errors at all to pass!! idk if this is real, but in reality, this candidate will be denied for sure. He actually says he doesn't know deep clone, and types many things wrong, and on top of it, he can't solve some questions. I solved all the questions, optimized it, and I was denied becuz I wasn't communicating too much with the interviewers. I remember I did talk throughout, maybe a few seconds I was thinking.

where are you from sir? Are you current employee at any software house?

@techsith In the 4th question, you told like we can pass function declaration as argument in function expression. I tried but not working. Please explain me if am wrong

22:25 can you please explain it more :)

Hey TS , I have a request for a new tutorial how can i contact you ?

My solution for : Finding missing number from an array(Sorted or Unsorted does not matter) const findMissingNumberInArray = arr => { const newArray = [...Array(arr.length+1).keys()].slice(); let missing = 0; newArray.forEach(el => { missing = arr.includes(el) ? missing : el // .indeOf(el) > -1 also works. }); return missing; } complexity : memory : its taking new memory . Algo : O(n) for loop + O(1) for find ==> O(n) ?? is it right here?

You got this white nuts in your hands, well done. You know i am so happy. And at the end he did understand the interview was fake? The reverse letters you felt in the trap, and the integer divsion with the remainder He did had to know. Also he should arrange the meta deta he had to itterate. I found the first 1 difficult, returning a function expression and using numb1 and the second value in numb3. You know in the Netherlands the jobs at the goverment Central Burea for statistics does have an innovation lab and at that department only white creative people work. At least they are creative i admit, but it is sad programmers like me with lot of experience dont get a job because we look crazy or if you dont share the ideas of the most of the conservative people that work at a company. There is always a certain culture at a company where you dont fit in, but that should not result into not hiring the person.

function createLogFunction(val) { return function() { console.log(val); }; } const functions3 = []; for (var i = 0; i < 3; i++) { functions3.push(createLogFunction(i)); console.log(functions3) } functions3.forEach(f => f()); I was asked this question, what will be output. could you please tell me what is the point in this question.

Bro, waiting for yours response for my query at your twitter & facebook page.

const sortedArray1 = array1.sort((a,b) => a-b); console.log(sortedArray1); // gives sorted array1 let len = array1.length; console.log("Length of array1 is: "+len); // printing length const sum = sortedArray1.reduce((a,c) => (a+c)); // reducing the array1 into its sum of elements console.log(sum); // printing sum const seriesSum = (len+1) * (len+2)/2; // sum of all elements including the missing one also let missingNumber =(seriesSum - sum); // getting missing element console.log("Missing number is: "+missingNumber); // printing missing numb. sortedArray1.splice(missingNumber-1,0,missingNumber); // inserting to its correct position console.log(sortedArray1); // finally printing it

you are the best :-)

What is that online video editor you are using?

I love these videos, thx!!!!!