Shyplite Questions

shyplite-questions.js

// Question 1: Create an Array from 0...100 without using traditional For-loop
function getNumbers(from, to) {
    let arr = [];
    while (from <= to) {
        arr.push(from);
        from++;
    }
    return arr;
}

let collection = getNumbers(0, 100);
console.log({collection});


// Question 2: Create an Array of only even numbers from the above array

let evenNumbers = collection.filter((n) => n%2 == 0);
console.log({evenNumbers});


// Create a function that returns a Promise which returns the
// square of only even numbers and
// throws an error if an odd number is passed

function checkEvenAndMakeSquare(n) {
    return new Promise((resolve, reject) => {
        if (n%2 == 0) {
            return resolve(n*n);
        }
        return reject(new Error("Odd number is passed."));
    })
}

// Question 3: create an array of even squares using the previous array
// direct invocation is important to see if the
// candidate understands Arrow functions correctly.

evenSquares = [];
evenNumbers.forEach(async n => {
    try {
        let ns = await checkEvenAndMakeSquare(n);
        evenSquares.push(ns);
    } catch (error) {
        console.log(error);
    }
    if (n == 10) {
        console.log({evenSquares});
    }
});


// Question 4: Sum of all the squares from the above array of Even Squares
setImmediate(() => {
    let sumOfEvenSquares = 0;
    evenSquares.forEach(n => {
        sumOfEvenSquares = sumOfEvenSquares + n;
    })
    console.log({ sumOfEvenSquares });
});

// Question 5: Call the above square Promise function with all numbers from 0-100
// and ensure that the errors are not thrown
// then print the following:
// 1. Number of errors
// 2. The resultant array
// 3. Number of objects in the resultant array

let resultArr = [], errorCount = 0;
collection.forEach(async n => {
    try {
        let ns = await checkEvenAndMakeSquare(n);
        resultArr.push(ns);
    } catch (error) {
        errorCount++;
    }
    if (n == collection[collection.length - 1]) {
        console.log({ resultArr, errorCount, resultArrCount: resultArr.length });
    }
});