Set a custom start and end range in an array that displays a random string?

August 28, 2022

I am playing around with JavaScript while preparing for my junior developer interview.

I am trying to write a function that accepts two parameters, a beginning point and an ending point, in an array. This function should generate a random name within a custom start and end point of the array. I seemed close to getting it right, but it displays NaN. What is NaN?

Here is the code I wrote.

const names = ['Kitana', 'Liu Kang', 'Sonya Blade', 'Johnny Cage', 'Jax Briggs', 'Smoke', 'Sheeva', 'Jade']

const section = document.querySelector('section')

const para = document.createElement('p');

// Add your code here
function random(beginIndex, endIndex) {
  for (let beginIndex = 0; beginIndex < names.length; beginIndex = beginIndex + endIndex) {

    let newRangeOfIndices = names[beginIndex]

    const randomName = Math.floor(Math.random() * newRangeOfIndices)

    para.textContent = randomName
  }
}

random(2, 5)

// Don't edit the code below here!

section.innerHTML = ' ';

section.appendChild(para);

<section></section>

You will notice that I already set a custom limit in the function to be run, 2 to 5. But it’s still not working. Please help me out.

>Solution :

You don’t for loop to get a random number.

To get a random index.

let randomIndex = Math.floor(Math.random() * (endIndex - beginIndex + 1) + beginIndex)

Then get the random name from the names array.

let randomName = names[randomIndex]

const names = ['Kitana', 'Liu Kang', 'Sonya Blade', 'Johnny Cage', 'Jax Briggs', 'Smoke', 'Sheeva', 'Jade']

const section = document.querySelector('section')

const para = document.createElement('p');

// Add your code here
function random(beginIndex, endIndex) {
    let randomIndex = Math.floor(Math.random() * (endIndex - beginIndex + 1) + beginIndex)  
    let randomName = names[randomIndex]

    para.textContent = randomName
}

random(2, 5)

// Don't edit the code below here!

section.innerHTML = ' ';

section.appendChild(para);