Comparing various indexes within an array using JavaScript array functions

I am currently facing a challenge with comparing non-consecutive indexes in an array. For instance, how can I compare index 0 with all the other indexes until reaching index 3 in a given array like this:

const arr = ["Juan", "Maria", "Maria", "Juan"]

In this scenario, comparing index 1 and 2 is easy, but how do I compare index 0 with all others sequentially until matching index 3?

Task Input: USA, AUSTRALIA, AUSTRALIA, INDIA, FRANCE, USA

Display the name of the country followed by "Bingo" if it is repeated consecutively

Display the name of the country followed by "Hooray" if it is repeated but not consecutive

Note: Utilize any Array method

Expected output: "Bingo Australia" "Hooray USA"

This is my attempt so far.

It should be noted that my current approach works because I am accessing countries[index + 5].

How can I dynamically increase the index after each iteration?

const countries = ['USA', 'Australia', 'Australia', 'France', 'India', 'USA'];

countries.forEach((value, index) => {
    if (countries[index] === countries[index + 1]) {
        console.log(`Bingo ${value}`);
    } else if (countries[index] === countries[index + 5]) {
        console.log(`Hooray ${value}`);
    }
});

Answer №1

If you're looking for a way to tackle this issue, you might consider the following approach:

Here's an example using an array of countries: ['USA', 'Australia', 'Australia', 'France', 'India', 'USA'].

By using nested forEach loops, you can check for repeated values and determine their positions in the array. 

Answer №2

A solution that utilizes multiple 'if' statements to optimize loop iterations and reduce redundant checks, ultimately achieving the same outcome as a nested loop.

const cArr = [1, 4, 5, 5, 6, 7, 4, 1];
let j = 0;
let fullCount = 0; // track loop count

for (let i = 0; i < cArr.length; ++i) {
  if (j === 0 && cArr[i] === cArr[i + 1]) { // check condition only in the first loop
    console.log('Bingo', cArr[i]);
  }

  if (i + 2 < cArr.length && cArr[j] === cArr[i + 2]) { // avoid accessing elements outside array
    console.log('Hooray', cArr[i + 2]);
    cArr[j] = null;
  }

  if (j > 0 && cArr[j] === null) { // check neighboring elements
    i = j;
    ++j;
  }
  if (j > 0 && i === cArr.length - 3) { // avoid empty loop
    i = j;
    ++j;
  }
  if (i === cArr.length - 1) { // increment j in the first loop
    i = j;
    ++j;
  }
  if (j === cArr.length - 2) { // stop loop when j reaches the second-to-last element
    i = cArr.length;
  }
  ++fullCount;
}

console.log(fullCount, " :loops count");

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