reflex_copy/reflex/.templates/web/utils/helpers/range.js

/**
 * Simulate the python range() builtin function.
 * inspired by https://dev.to/guyariely/using-python-range-in-javascript-337p
 *
 * If needed outside of an iterator context, use `Array.from(range(10))` or
 * spread syntax `[...range(10)]` to get an array.
 *
 * @param {number} start: the start or end of the range.
 * @param {number} stop: the end of the range.
 * @param {number} step: the step of the range.
 * @returns {object} an object with a Symbol.iterator method over the range
 */
export default function range(start, stop, step) {
  return {
    [Symbol.iterator]() {
      if (stop === undefined) {
        stop = start;
        start = 0;
      }
      if (step === undefined) {
        step = 1;
      }

      let i = start - step;

      return {
        next() {
          i += step;
          if ((step > 0 && i < stop) || (step < 0 && i > stop)) {
            return {
              value: i,
              done: false,
            };
          }
          return {
            value: undefined,
            done: true,
          };
        },
      };
    },
  };
}