AugurProject/augur-ui

import { compose, inRange, floor, map, sortedUniq } from "lodash/fp";
import { limitPeriodByRange } from "modules/markets/helpers/limit-period-by-range";

const getMiddleElementOfArray = (arr = []) => {
  const l = arr.length;
  const i = floor(l / 2);

  return arr[i];
};

const getMiddleDuration = compose(
  getMiddleElementOfArray,
  sortedUniq,
  map("duration")
);

/**
 * @typedef {Object} Duration
 * @property {string} label
 * @property {number} duration
 * @property {boolean} [isDefault]
 */

/**
 * We need to ensure the currently selected period is valid. If not, we need to select the closest valid one.
 * @param {Duration[]} fullPeriodList - The possible periods we can select from.
 * @param {number} [selectedRange] - The duration of the selectedRange. If omitted, return min period value.
 * @param {number} [selectedPeriod] - The duration of the selectedPeriod. If omitted, return nearest.
 *
 * @return {number} - The duration of the clamped period.
 */
export const clampPeriodByRange = (
  fullPeriodList,
  selectedRange,
  selectedPeriod
) => {
  if (!selectedRange) return null;

  if (inRange(0, selectedRange)(selectedPeriod)) return selectedPeriod;

  const limitedPeriods = limitPeriodByRange(fullPeriodList, selectedRange);
  return getMiddleDuration(limitedPeriods);
};