Python has a very handy range array function that I find myself using all the time. Unfortunately JavaScript does not, but we can quickly implement our own functionality.

Note: This code comes, with only very small tweaks, from Chris West’s initial implementation on his blog.

function range(start, edge, step) {
  // If only 1 number passed make it the edge and 0 the start
  if (arguments.length === 1) {
    edge = start;
    start = 0;
  }

  // Validate edge/start
  edge = edge || 0;
  step = step || 1;

  // Create array of numbers, stopping before the edge
  let arr = [];
  for (arr; (edge - start) * step > 0; start += step) {
    arr.push(start);
  }
  return arr;
}

range(10); // [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
range(3, 5); // [3, 4]
range(10, 20, 2); // [10, 12, 14, 16, 18]



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