有几件事你可以尝试，但这个（不太优雅的）解决方案应该会给予你想要的结果：

export default class someController extends Controller {
  @tracked errorlist = [];
  @action
  someAction {
    const that = this;
    RSVP.allSettled(promises).then(function (retarray) {
      retarray.forEach((retstate) => {
        if (retstate.state == 'rejected') {
          that.errorlist.push(retstate.reason);
        }
      });
    });
  }
}

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就我个人而言，我会将errorlist.push移动到控制器上自己的方法中，这样你就可以调用这样的东西：

export default class someController extends Controller {
  @tracked errorlist = [];
  @action
  someAction {
    RSVP
      .allSettled(promises)
      .then((retarray) => retarray.forEach(this.addToErrorIfRejected));
  }
  @action
  addToErrorIfRejected({ state, reason }) {
    if (state == 'rejected') this.errorlist.push(reason);
  }
}

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