get-summer.js

import * as seasons from './seasons';

/**
 * @param {number} month
 * @returns {season}
 **/
const getSummer = (month) => {
    if ([5, 6, 7].includes(month)) {
        return seasons.SUMMER;
    }

    return null;
}

/**
 * @typedef {import('./interfaces').season} season
 */