Exams - String Matrix Rotation

/* You are given a sequence of text lines. Assume these text lines form a matrix of characters
(pad the missing positions with spaces to build a rectangular matrix). Write a program to rotate
the matrix by 90, 180, 270, 360, … degrees. Print the result at the console as sequence of strings. */

"use strict";

function rotateTheMatrix(arr) {
    var rotate = parseInt(arr[0].substring(7, arr[0].length - 1)) % 360;

    var matrix = [];
    var maxLength = 1;
    for (var i = 1; i < arr.length; i += 1) {
        var matrixRow = arr[i].split('').filter(Boolean);
        if (matrixRow.length > maxLength) {
            maxLength = matrixRow.length;
        }
        matrix.push(matrixRow);
    }

    for (i = 0; i < matrix.length; i += 1) {
        while (matrix[i].length < maxLength) {
            matrix[i].push(' ');
        }
    }

    var output = '';
    if (rotate == 0) {
        for (i = 0; i < matrix.length; i += 1) {
            output = output.concat(matrix[i].join('')).concat('\n');
        }
        return output;
    }

    if (rotate == 180) {
        for (i = matrix.length - 1; i >= 0; i -= 1) {
            var rowStr = matrix[i].reverse().join('');
            output = output.concat(rowStr).concat('\n');
        }
        return output;
    }

    var rotatedArr = new Array(maxLength);
    for (i = 0; i < rotatedArr.length; i += 1) {
        rotatedArr[i] = [];
        for (var j= matrix.length - 1; j >= 0; j -= 1) {
            rotatedArr[i].push(matrix[j][i]);
        }
    }

    if (rotate == 90) {
        for (i = 0; i < rotatedArr.length; i += 1) {
            rowStr = rotatedArr[i].join('');
            output = output.concat(rowStr).concat('\n');
        }
        return output;
    }

    if (rotate == 270) {
        for (i = rotatedArr.length - 1; i >= 0; i -= 1) {
            rowStr = rotatedArr[i].reverse().join('');
            output = output.concat(rowStr).concat('\n');
        }
        return output;
    }
}

console.log(rotateTheMatrix([ 'Rotate(90)', 'hello', 'softuni', 'exam' ]));
console.log(rotateTheMatrix([ 'Rotate(180)', 'hello', 'softuni', 'exam' ]));
console.log(rotateTheMatrix([ 'Rotate(270)', 'hello', 'softuni', 'exam' ]));
console.log(rotateTheMatrix([ 'Rotate(720)', 'js', 'exam' ]));