Function waitForFunction

test/helpers/wait-for.js:14–48

* Waits for specified function to resolve to a truthy value. * * @param {Function} fn function to be evaluated until truthy * @param {*} arg optional argument to pass to `fn` * @param {Object} options optional parameters * @returns {Promise} promise which resolves to function result

(fn, arg, options = {})

 * @returns {Promise} promise which resolves to function result
 */
function waitForFunction(fn, arg, options = {}) {
  const settings = {
    ...defaults,
    ...options,
  };

  return new Promise((resolve, reject) => {
    let timeElapsed = 0;

    const int = setInterval(() => {
      let result;

      try {
        result = fn(arg);
      } catch (e) {
        // Continue...
      }

      if (result) {
        clearInterval(int);
        resolve(result);
      }

      timeElapsed += settings.delay;

      if (timeElapsed >= settings.timeout) {
        const msg = `waitForFunction did not return a truthy value (${
          settings.timeout
        } ms): ${fn.toString()}\n`;

        reject(msg);
      }
    }, settings.delay);
  });
}

/**
 * Waits for specified CSS selector to be located in the DOM