更新特定文档时如何从 mongoDb 获取完整文档？

Question

实际上，我正在 Node.js (Express.js) 中处理变更流。我陷入了以下情况。

这里我使用 mongoose

与 mongoDB 建立了数据库连接

async function main() {
    const uri = process.env.DATABASE;
    const client = mongoose.connect(uri, {
        useNewUrlParser: true,
        useCreateIndex: true,
        useUnifiedTopology: true,
        reconnectInterval: 500, // Reconnect every 500m
    })

    // Connect to the MongoDB cluster
    await client
        .then(() => console.log('DB Connected'))
        .catch(er => console.log(er));


    const pipeline = [
        {
            '$match': {
                $or: [{ operationType: 'insert' }, { operationType: 'update' }]

            }
        }
    ];
    await monitorListingsUsingEventEmitter(client, 30000,pipeline);



}

main().catch(console.error);

这是改变流的函数


async function monitorListingsUsingEventEmitter(client, timeInMs = 60000, pipeline = []) {


    const changeStream = await members.watch(pipeline);

    changeStream.on('change', async (next) => {
        switch (next.operationType) {
            case 'insert':
                console.log('an insert happened...', "uni_ID: ", next.fullDocument);
                break;

            case 'update':
                console.log('an update happened...', next.fullDocument);
//
//getting undefined in above line because there is no property name 'fullDocument' in object next
//      
                break;

            case 'delete':
                console.log('a delete happened...');
                break;

            default:
                break;
        }

    });

总的来说，我的问题是：

I need a full document object that is getting updated without any query

Answer 1

我得到了答案。我刚刚检查了 https://www.mongodb.com/docs/manual/reference/method/db.collection.watch/.

其实我用过

const changeStream = await members.watch(pipeline);

上面的语句应该是这样的。它现在工作

const changeStream = await members.watch(pipeline, { fullDocument: "updateLookup" }
//this actual answer

感谢大家不回覆:) 我终于做到了

更新特定文档时如何从 mongoDb 获取完整文档？

how to get fullDocument from mongoDb when partlicular document is updated?

node.js

mongodb

express

mongoose

changestream