import pLimit from '../../../p-limit@4.0.0/node_modules/p-limit/index.mjs';

class EndError extends Error {
  constructor(value) {
    super();
    this.value = value;
  }
}

// The input can also be a promise, so we await it.
const testElement = async (element, tester) => tester(await element);

// The input can also be a promise, so we `Promise.all()` them both.
const finder = async element => {
  const values = await Promise.all(element);
  if (values[1] === true) {
    throw new EndError(values[0]);
  }
  return false;
};
async function pLocate(iterable, tester, {
  concurrency = Number.POSITIVE_INFINITY,
  preserveOrder = true
} = {}) {
  const limit = pLimit(concurrency);

  // Start all the promises concurrently with optional limit.
  const items = [...iterable].map(element => [element, limit(testElement, element, tester)]);

  // Check the promises either serially or concurrently.
  const checkLimit = pLimit(preserveOrder ? 1 : Number.POSITIVE_INFINITY);
  try {
    await Promise.all(items.map(element => checkLimit(finder, element)));
  } catch (error) {
    if (error instanceof EndError) {
      return error.value;
    }
    throw error;
  }
}

export { pLocate as default };
