Function pool

lib/index.js:6644–6690

(promiseFactories, limit)

function pool(promiseFactories, limit) {
  return new Promise(function (resolve, reject) {
    var running = 0;
    var current = 0;
    var done = 0;
    var len = promiseFactories.length;
    var err;

    function runNext() {
      running++;
      promiseFactories[current++]().then(onSuccess, onError);
    }

    function doNext() {
      if (++done === len) {
        /* istanbul ignore if */
        if (err) {
          reject(err);
        } else {
          resolve();
        }
      } else {
        runNextBatch();
      }
    }

    function onSuccess() {
      running--;
      doNext();
    }

    /* istanbul ignore next */
    function onError(thisErr) {
      running--;
      err = err || thisErr;
      doNext();
    }

    function runNextBatch() {
      while (running < limit && current < len) {
        runNext();
      }
    }

    runNextBatch();
  });
}

const CHANGES_BATCH_SIZE = 25;
const MAX_SIMULTANEOUS_REVS = 50;