Iterate over a matrix in JavaScript, cell by cell

flatter.js

function* flatten(matrix) {
  for (var i = 0; i < matrix.length; i += 1) {
    let column = matrix[i];
    
    if (!Array.isArray(column)) yield column;
    
    for (var j = 0; j < column.length; j += 1) {
      yield column[j];
    }
  }
}

how_to_use.js

const matrix = [
  [1, 2],
  [3, 4]
];

const walker = flatten(matrix);

console.log(walker.next().value); // 1
console.log(walker.next().value); // 2
console.log(walker.next().value); // 3
console.log(walker.next().value); // 4

console.log(walker.next().value); // undefined