Perform Matrix Multiplication in JavaScript

const N = 3;

function multiplyMatrices(a, b) {
  const result = [];
  for (let i = 0; i < N; i++) {
    result[i] = [];
    for (let j = 0; j < N; j++) {
      result[i][j] = 0;
    }
  }
  for (let i = 0; i < N; i++) {
    for (let j = 0; j < N; j++) {
      for (let k = 0; k < N; k++) {
        result[i][j] += a[i][k] * b[k][j];
      }
    }
  }
  return result;
}

function displayMatrix(matrix) {
  for (let i = 0; i < N; i++) {
    console.log(matrix[i].join("\t"));
  }
}

const firstMatrix = [
  [1, 2, 3],
  [4, 5, 6],
  [7, 8, 9],
];
const secondMatrix = [
  [9, 8, 7],
  [6, 5, 4],
  [3, 2, 1],
];

const result = multiplyMatrices(firstMatrix, secondMatrix);

console.log("First Matrix:");
displayMatrix(firstMatrix);
console.log("\nSecond Matrix:");
displayMatrix(secondMatrix);
console.log("\nResult Matrix:");
displayMatrix(result);

const N = 2;

function multiplyMatrices(a, b) {
  const result = [];
  for (let i = 0; i < N; i++) {
    result[i] = [];
    for (let j = 0; j < N; j++) {
      result[i][j] = 0;
      for (let k = 0; k < N; k++) {
        result[i][j] += a[i][k] * b[k][j];
      }
    }
  }
  return result;
}

function printMatrix(title, m) {
  console.log(title);
  for (let i = 0; i < N; i++) {
    console.log(m[i].join(" "));
  }
}

const a = [[1, 2], [3, 4]];
const b = [[5, 6], [7, 8]];
const r = multiplyMatrices(a, b);

printMatrix("A", a);
console.log();
printMatrix("B", b);
console.log();
printMatrix("AB", r);

function canMultiply(a, b) {
  if (!a.length || !b.length || !a[0].length || !b[0].length) {
    return false;
  }
  const colsA = a[0].length;
  const rowsB = b.length;
  if (colsA !== rowsB) {
    return false;
  }
  const colsB = b[0].length;
  for (let i = 0; i < a.length; i++) {
    if (a[i].length !== colsA) {
      return false;
    }
  }
  for (let i = 0; i < b.length; i++) {
    if (b[i].length !== colsB) {
      return false;
    }
  }
  return true;
}

function multiplySafe(a, b) {
  if (!canMultiply(a, b)) {
    return null;
  }
  const m = a.length;
  const n = a[0].length;
  const p = b[0].length;
  const result = Array.from({ length: m }, () => Array(p).fill(0));
  for (let i = 0; i < m; i++) {
    for (let j = 0; j < p; j++) {
      for (let k = 0; k < n; k++) {
        result[i][j] += a[i][k] * b[k][j];
      }
    }
  }
  return result;
}

const ok = multiplySafe([[1, 2, 3], [4, 5, 6]], [[7, 8], [9, 10], [11, 12]]);
const bad = multiplySafe([[1, 2], [3, 4]], [[5, 6, 7]]);
console.log(JSON.stringify(ok));
console.log(bad);