jolt.loader.js

async function getManyUsers(ids) {
  console.log("getManyUsers", ids);
  return ids.map(id => ({ id, name: "name " + id }));
}

function arrayToMap(arr) {
  const map = new Map();
  arr.forEach(result => {
    map.set(result.id, result);
  });
  return map;
}

function throttleGetManyFn(fn, throttle) {
  let count = 0;
  return new Promise((resolve, reject) => {});
}

function createLoader(getMany, opts) {
  let queue = [];
  let flushesCount = 0;

  const { throttle } = opts || {};

  async function flush() {
    if (!queue.length) return;
    console.log("Flush", queue);
    const oldQueue = queue;
    queue = [];

    const ids = oldQueue.map(({ id }) => id);
    const uniqueIds = Array.from(new Set(ids));

    const results = await getMany(uniqueIds);
    const resultsMap = arrayToMap(results);
    return oldQueue.map(({ id, resolve, reject }) => {
      const result = resultsMap.get(id);
      resolve(result);
    });
  }

  setInterval(flush, 1000); // configurable

  return function getOne(id) {
    return new Promise(async (resolve, reject) => {
      queue.push({ id, resolve, reject });
    });
  };
}

(async function main() {
  const getOneUser = createLoader(getManyUsers);
  const promises = [getOneUser(1), getOneUser(2), getOneUser(3)];
  console.log("Got", await Promise.all(promises));
})();