JS Problems

Question 1

Find the smallest integer in an array

Answer 1

class SmallestIntegerFinder {
      findSmallestInt(args) {
      return Math.min(...args)
    }
}
or
const arr = [2, 3, 1];
console.log(Math.min(...arr));

Question 2

Write a function that converts the input string to uppercase

Answer 2

function makeUpperCase(str) {
      return str.toUpperCase( );
}
or
const str = 'hello world';
console.log(str.toUppercase( ));

Question 3

Build a function that returns an array of integers from n to 1 where n>0

Answer 3

const reverseSeq = n => {
     let arr = [ ];
     for (let i=n; i>0, i--) {
     arr.push(i);
     } return arr;
};

Question 4

You are given the length and width of a 4-sided polygon. The polygon can either be a rectangle or a square. If it’s a square, return its area. If it’s a rectangle, return its perimeter.

Answer 4

const areaOrPerimeter = function(l, w) {
     return l === w ? l * w : (l + w) * 2;
};

Question 5

Create a function that answers the question “Are you playing banjo?” If your name starts with the letter “R” or lowercase “r”, you are playing banjo!
The function takes a name as its only argument, and returns one of the following strings:
name + “plays banjo”
name + “does not play banjo”

Answer 5

function areYouPlayingBanjo(name) {
     if (name[0] == 'R' || name[0] == 'r')
     return name + "plays banjo";
}else {
     return name + "does not play banjo";
}
or
function areYouPlayingBanjo(name) {
     if (name[0].toLowerCase( ) == 'r') {
     return name + 'plays banjo';
}else {
     return name + 'does not play banjo';
   }
}

Question 6

The cockroach is one of the fastest insects. Write a function that takes its speed in km per hour and returns it in cm per second, rounded down to the integer (=floored).

Answer 6

function cockroachSpeed(s) {
     return Math.floor(s*100000/3600);
}
or
function cockroachSpeed(s) {
     const secsInHour = 3600;
     const centimetersInKilometers = 100000;
     return Math.floor((s*centimetersInKilometers)/secsInHour);
}

Question 7

Given an array of integers as strings and numbers, return the sum of the array values as if all were numbers. Return your answer as a number.

Answer 7

function sumMix(x) {
     return x.map(a => +a).reduce((a, b) => a + b);
}

Question 8

Given a non-empty array of integers, return the result of multiplying the values together in order.

Answer 8

function grow(x) {
     return x.reduce((a, b) => a * b);

Question 9

Write a program that finds the summation of every number from 1 to num. The number will always be a positive integer greater than 0.

Answer 9

var summation = function (num) {
     let result = 0;
     for (var i = i; i <= num; i++) {
     result += i;
}
     return result;
}

Question 10

You get an array of numbers, return the sum of all the positive ones. If there is nothing to sum the sum default is 0.

Answer 10

function positiveSum(arr) {
     return arr.reduce((a, b) => a + (b > 0 ? b : 0), 0);
}

Question 11

Write a function called repeatStr which repeats the given string exactly n times.

Answer 11

function repeatStr (n, s) {
     return s.repeat(n);
}