react-query/lib/createAsyncStoragePersister/asyncThrottle.js

Hooks for managing, caching and syncing asynchronous and remote data in React

"use strict";

exports.__esModule = true;
exports.asyncThrottle = asyncThrottle;

const noop = () => {
  /* do nothing */
};

function asyncThrottle(func, {
  interval = 1000,
  onError = noop
} = {}) {
  if (typeof func !== 'function') throw new Error('argument is not function.');
  let running = false;
  let lastTime = 0;
  let timeout;
  let currentArgs = null;

  const execFunc = async () => {
    if (currentArgs) {
      const args = currentArgs;
      currentArgs = null;

      try {
        running = true;
        await func(...args);
      } catch (error) {
        onError(error);
      } finally {
        lastTime = Date.now(); // this line must after 'func' executed to avoid two 'func' running in concurrent.

        running = false;
      }
    }
  };

  const delayFunc = async () => {
    clearTimeout(timeout);
    timeout = setTimeout(() => {
      if (running) {
        delayFunc(); // Will come here when 'func' execution time is greater than the interval.
      } else {
        execFunc();
      }
    }, interval);
  };

  return (...args) => {
    currentArgs = args;
    const tooSoon = Date.now() - lastTime < interval;

    if (running || tooSoon) {
      delayFunc();
    } else {
      execFunc();
    }
  };
}