convert flat array to 2D array in typescript

Question

I have a flat array like this

['-', '-', '-', '-', '-', '-', '-', '-', '-']

and I want to convert it to be 2D like this

[
  ['-', '-', '-'],
  ['-', '-', '-'],
  ['-', '-', '-']
]

I saw this question but it is in javascript and I am getting error on declaring types of the "list" and "elementsPerSubArray"

// declaring type of list and elementsPerSubArray
function listToMatrix(list: number[], elementsPerSubArray: number) {
    var matrix = [], i, k;

    for (i = 0, k = -1; i < list.length; i++) {
        if (i % elementsPerSubArray === 0) {
            k++;
            matrix[k] = [];
        }
        // here I am facing error says " Argument of type 'number' is not assignable to parameter of type 'never' "
        matrix[k].push(list[i]);
    }

    return matrix;
}

var matrix = listToMatrix([1, 2, 3, 4, 4, 5, 6, 7, 8, 9], 3);

score 2 · Accepted Answer · answered Jul 01 '23 at 17:18

TypeScript is giving you an error because it can't figure out the type of the matrix variable.
code:

function listToMatrix(list: number[], elementsPerSubArray: number) {
  var matrix: number[][] = []; // Specify the type as number[][]

  for (let i = 0, k = -1; i < list.length; i++) {
    if (i % elementsPerSubArray === 0) {
      k++;
      matrix[k] = [];
    }
    matrix[k].push(list[i]);
  }

  return matrix;
}

var matrix = listToMatrix([1, 2, 3, 4, 4, 5, 6, 7, 8, 9], 3);
console.log(matrix);

Output:

convert flat array to 2D array in typescript

1 Answers1