index.js

const functions = require('firebase-functions');
const admin = require('firebase-admin');
const express = require('express');
const cors = require('cors');
const app = express();

admin.initializeApp();
app.use(cors({ origin: true }));

// Distributed counters Like Post
app.post("/like2/:id", async (req, res) => {
    const doc = await admin.firestore().collection('posts').doc(req.params.id).get();
    const increment = admin.firestore.FieldValue.increment(1)

    if (!doc.exists) {
        return res.status(404).send({"message":"找不到文章！"});
    }

    //1~10
    await admin.firestore().collection('posts').doc(req.params.id).collection("likeCounter").doc("likeCount_"+(Math.floor(Math.random()*10)+1).toString())
    .set({count: increment}, {merge: true});
    res.status(201).send({"message":"按讚成功！"});
});


exports.post= functions.https.onRequest(app);