A mini https://github.com/facebook/dataloader

baby-dataloader.js

function createLoader (keysTask) {
  let keys = []
  let nextTaskPromise

  return {
    load (key) {
      const index = keys.push(key) - 1;

      if (!nextTaskPromise) {
        let resolver
        nextTaskPromise = new Promise((resolve, reject) => {
          resolver = { resolve, reject };
        });

        setTimeout(() => {
          keysTask(keys).then(resolver.resolve, resolver.reject);
          keys = [];
          nextTaskPromise = null;
        }, 50);
      }

      return nextTaskPromise.then(results => results[index]);
    }
  };
}