Gcp/Firebase/Firestore/async

通常のfirestore取得をasync/awaitに変更する方法

functionにasyncを追加し、firestoreのget()にawaitを追加すればよい。

async/awaitを使わないfirestoreのサンプル

const functions = require('firebase-functions');
const admin = require('firebase-admin');
admin.initializeApp();
exports.db = functions
  .region('asia-northeast1')
  .https.onRequest((request, response) => {
  admin.firestore().collection('scores')
        .orderBy('maxKanaSpeed', 'desc')
        .limit(50)
        .get()
        .then((snapshot) =>
      {
        var scores = snapshot.docs.map(x => x.data());
        var json = JSON.stringify(scores);
        response.send("json" + json);
  });
});

async/awaitを使うfirestoreのサンプル

exports.dbasync = functions
  .region('asia-northeast1')
  .https.onRequest(async(request, response) => {
      var snapshot = await admin.firestore().collection('scores')
        .orderBy('maxKanaSpeed', 'desc')
        .limit(50)
        .get();
      var scores = snapshot.docs.map(x => x.data());
      var json = JSON.stringify(scores);
      response.send("json" + json);
});

dbのsum

exports.helloWorld = functions
  .region('asia-northeast1')
  .https.onRequest(async(request, response) => {
  const count = 50;
  var snapshot = await admin.firestore().collection('users')
        .orderBy('age', 'desc')
        .limit(count)
        .get();
  const sum = snapshot.docs
        .map(doc => doc.data().age)
        .reduce((prev, current) => prev + current, 0);
 console.log( "sum=" + sum.toString() );
});