@chevre/domain/example/src/mongoConnectionList.ts

Chevre Domain Library for Node.js

// tslint:disable:no-console no-magic-numbers no-null-keyword
import * as mongoose from 'mongoose';

const MONGOLAB_URI = String(process.env.MONGOLAB_URI);

interface IConnectionByAppName {
    connection: mongoose.Connection;
    isReady: boolean;
}
const uniqueConnections: Record<string, IConnectionByAppName> = {};
export async function getUniqueConnectionByAppName(params: { appName: string }): Promise<mongoose.Connection> {
    const { appName } = params;
    if (uniqueConnections[appName] === undefined) {
        uniqueConnections[appName] = {
            connection: mongoose.createConnection(MONGOLAB_URI, { appName }),
            isReady: false
        };
        uniqueConnections[appName].connection.on('connected', () => console.log('connected'));
        uniqueConnections[appName].connection.on('open', () => console.log('open'));
        uniqueConnections[appName].connection.on('disconnected', () => console.log('disconnected'));
        uniqueConnections[appName].connection.on('reconnected', () => console.log('reconnected'));
        uniqueConnections[appName].connection.on('disconnecting', () => console.log('disconnecting'));
        uniqueConnections[appName].connection.on('close', () => console.log('close'));
    }
    const conectionByAppName = uniqueConnections[appName];

    if (!conectionByAppName.isReady) {
        console.log('connecting(asPromise)...');
        await conectionByAppName.connection.asPromise();
        conectionByAppName.isReady = true;
    } else {
        console.log('is ready.');
    }

    return conectionByAppName.connection;
}

async function main() {
    console.log(mongoose.connections.length, 'mongoose.connections found');

    mongoose.connection.on('connected', () => console.log('connected'));
    mongoose.connection.on('open', () => console.log('open'));
    mongoose.connection.on('disconnected', () => console.log('disconnected'));
    mongoose.connection.on('reconnected', () => console.log('reconnected'));
    mongoose.connection.on('disconnecting', () => console.log('disconnecting'));
    mongoose.connection.on('close', () => console.log('close'));
    // await mongoose.connect(MONGOLAB_URI);

    // const firstConnection = mongoose.createConnection(<string>process.env.MONGOLAB_URI);
    // firstConnection.on('connected', () => console.log('connected'));
    // firstConnection.on('open', () => console.log('open'));
    // firstConnection.on('disconnected', () => console.log('disconnected'));
    // firstConnection.on('reconnected', () => console.log('reconnected'));
    // firstConnection.on('disconnecting', () => console.log('disconnecting'));
    // firstConnection.on('close', () => console.log('close'));

    // tslint:disable-next-line:prefer-array-literal
    [...Array(10)].map(async (__, i) => {
        getUniqueConnectionByAppName({ appName: 'xxx' })
            .then(async (connectResult) => {
                console.log('connected:', connectResult.id, i);
                await getUniqueConnectionByAppName({ appName: 'xxx' });
            });
    });

    console.log(mongoose.connections.length, 'mongoose.connections found');

    // db.currentOp(true)
    //     .inprog.forEach((op) => {
    //         if (op.active = true && op.client != undefined) {
    //             const miniOp = {
    //                 client: op.client, description: op.desc
    //             };
    //             console.log(miniOp);
    //         }
    //     });
}

main()
    .catch(console.error);