Magic Matrices

(M) => {
    let isMagicMatrix = (m) => {
        let rows = m.length,
            cows = m[0].length,
            sum = 0;
        for(let i = 0; i < m[0].length; i++) {
            sum += m[0][i];
        }

        for(let i=1; i<rows; i++) {
            let sumIn = 0;
            for(let j = 0; j < m[i].length; j++) {
                sumIn += m[i][j];
            }
            if(sumIn !== sum) return false;
        }

        for(let i=0; i<cows; i++) {
            let vertSum = 0;
            for(let j=0; j<rows; j++) {
                vertSum += m[j][i];
            }
            if(vertSum !== sum) return false;
        }

        return true;
    }

    console.log(isMagicMatrix(M));
}