Function resolveAsyncComponent

static/vuejs/vue.js:3120–3166

(
  factory,
  baseCtor,
  cb
)

}

function resolveAsyncComponent (
  factory,
  baseCtor,
  cb
) {
  if (factory.requested) {
    // pool callbacks
    factory.pendingCallbacks.push(cb);
  } else {
    factory.requested = true;
    var cbs = factory.pendingCallbacks = [cb];
    var sync = true;

    var resolve = function (res) {
      if (isObject(res)) {
        res = baseCtor.extend(res);
      }
      // cache resolved
      factory.resolved = res;
      // invoke callbacks only if this is not a synchronous resolve
      // (async resolves are shimmed as synchronous during SSR)
      if (!sync) {
        for (var i = 0, l = cbs.length; i < l; i++) {
          cbs[i](res);
        }
      }
    };

    var reject = function (reason) {
      "development" !== 'production' && warn(
        "Failed to resolve async component: " + (String(factory)) +
        (reason ? ("\nReason: " + reason) : '')
      );
    };

    var res = factory(resolve, reject);

    // handle promise
    if (res && typeof res.then === 'function' && !factory.resolved) {
      res.then(resolve, reject);
    }

    sync = false;
    // return in case resolved synchronously
    return factory.resolved
  }
}

function extractProps (data, Ctor, tag) {
  // we are only extracting raw values here.