Find the two indexes of an array where their values equal a given target (O(n^2) solution)

sumArray.js

// function to check answer
function checkAnswer(arr, target, index1, index2) {
    return arr[index1] + arr[index2] === target;
}

// generate array with random numbers
const length = 100
const target = 90
const a = Array.from({ length }, () => Math.floor(Math.random() * 100)).sort()

// exhaustively search all possible values (O(n^2))
for (let i = 0; i < a.length; i++) {
    for (let j = i + 1; j < a.length - 1; j++) {
        if (checkAnswer(a, target, i, j)) {
            console.log(`First number = a[${i}] =`, a[i]);
            console.log(`Second number = a[${j}] =`, a[j]);
            process.exit(0)
        }
    }
}

// no solution found
console.log('No solution found')
process.exit(1)

To run:

curl -sL https://gist.githubusercontent.com/RhydianJenkins/8190b701621a59070e57fbbf1607333f/raw/2b9accf4ad4d79ea7d6ac87088f2e1bc9c83953c/sumArray.js | node