如何在 Firestore/Express.js 中的这种特定情况下地理查询使用“onSnapshot”方法

问题描述

我在这里有这个特定的代码：

const getEmergencies = async (body) => {
  const {
    responderId,latitude: responderLatitude,longitude: responderLongitude,} = body;

  // Store all filtered emergencies in here
  const filteredEmergencies = [];

  // Find emergencies within 10km of the location of the responder
  const center = [responderLatitude,responderLongitude];
  const radiusInM = 10 * 1000; // 10km

  // Each item in 'bounds' represents a startAt/endAt pair. We have to issue
  // a separate query for each pair. There can be up to 9 pairs of bounds
  // depending on overlap,but in most cases there are 4.
  const bounds = geofire.geohashQueryBounds(center,radiusInM);
  const promises = [];

  bounds.forEach((bound) => {
    const query = db
      .collection('emergencies')
      .orderBy('location.geohash')
      .startAt(bound[0])
      .endAt(bound[1]);

    promises.push(query.get());
  });

  // Collect all the query results together into a single list
  await Promise.all(promises)
    .then((snapshots) => {
      const emergencies = [];

      snapshots.forEach((snapshot) => {
        snapshot.docs.forEach((emergency) => {
          // This is the location of the emergency
          const { latitude,longitude } = emergency.get('location');

          // We have to filter out all emergencies that are
          // > 10km away from the responder
          const distanceInKm = geofire.distanceBetween(
            [latitude,longitude],center
          );
          const distanceInM = distanceInKm * 1000;
          if (distanceInM <= radiusInM) {
            emergencies.push({ emergency,distance: distanceInKm });
          }
        });
      });

      return emergencies;
    })
    .then(async (emergencies) => {
      await Promise.all(
        emergencies.map(async ({ emergency,distance }) => {
          const emergencyData = emergency.data();

          // We need to filter out emergencies if:
          // 1. Number of Responders is less than or equal to 3
          // 2. Status is ongoing
          if (
            emergencyData.numberOfResponders <= 3 &&
            emergencyData.status === 'ongoing'
          ) {
            // Additional filter for emergencies is to see
            // if the emergency was not declined by the responder
            const declinedRespondeRSSnapshot = await emergency.ref
              .collection('declinedResponders')
              .where('responderId','==',responderId)
              .get();

            // If the result is empty,then that means that
            // the responder has not declined this emergency.
            // So,we push this emergency to our filteredEmergencies array.
            if (declinedRespondeRSSnapshot.empty) {
              filteredEmergencies.push({
                ...emergencyData,emergencyId: emergency.id,distance,});
            }
          }
        })
      );
    });

  socket.emit('emergencies:get',filteredEmergencies);
};

我想将从此 API 创建的新“紧急情况”实时发送到客户端。我一直在寻找有关如何执行此操作的一段时间，但似乎找不到与我的情况类似的任何内容。我是否需要重构我的代码才能达到预期的结果？

解决方法

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