matrix spiral problem created by arrbxr - https://repl.it/@arrbxr/matrix-spiral-problem

index.js

function matrix(n) {
    let result = [];

    for(let i = 0; i < n; i++) {
        result.push([]);
    }

    let counter = 1;
    let startColun = 0;
    let endColumn = n - 1;
    let startRow = 0;
    let endRow = n - 1;

    while(startColun <= endColumn && startRow <= endRow) {
        // Top row 
        for(let i = startColun; i <= endColumn; i++) {
            result[startRow][i] = counter; 
            counter++;
        }
        startRow++;

        // Right column 
        for(let i = startRow; i <= endRow; i++) {
            result[i][endColumn] = counter;
            counter++;
        }
        endColumn--;

        // Bottom row 
        for(let i = endColumn; i >= startColun; i--) {
            result[endRow][i] = counter;
            counter++;
        }
        endRow--;

        // start column
        for(let i = endRow; i >= startRow; i--) {
            result[i][startColun] = counter;
            counter++;
        }
        startColun++;
    }

    return result;
}

matrix(5);