Generate a range or interpolated section with generators

range.js

let range = (start, end, step) => {
  return {
    *[Symbol.iterator]() {
      for (let n = start; n < end; n += step) {
        yield n;
      }
    },
  };
};

let interpolate = (start, end, segmentCount) => {
  let span = end - start;
  let stepSize = span / segmentCount;
  return {
    *[Symbol.iterator]() {
      yield start;
      for (let n = 1; n < segmentCount; n++) {
        yield start + stepSize * n;
      }
      yield end;
    },
  };
};