Next.js with-mongodb convert to TypeScript-CodePudding

I installed next.js app with mongodb template:

npx create-next-app --e with-mongodb my-app

and installed TypeScript as well. And i need to convert /lib/mongodb.js to TypeScript

Currently it looks like this, almost no type change

// lib/mongodb.ts

import { MongoClient } from 'mongodb'

const uri = process.env.MONGODB_URI
const options = {}

let client
let clientPromise: MongoClient

if (!process.env.MONGODB_URI) {
  throw new Error('Please add your Mongo URI to .env.local')
}
if (process.env.NODE_ENV === 'development') {
  if (!global._mongoClientPromise) {
    client = new MongoClient(uri, options)
    global._mongoClientPromise = client.connect()
  }
  clientPromise = global._mongoClientPromise
} else {
  client = new MongoClient(uri, options)
  clientPromise = client.connect()
}

export default clientPromise

And it is yelling: Please, help me to define proper types, i'm pretty to TypeScript! Thanks in advance!

CodePudding user response：

I ran into the same problem yesterday. Luckily, found a solution!

import { MongoClient } from "mongodb";

if (!process.env.MONGODB_URI) {
  throw new Error("Please add your Mongo URI to .env.local");
}

const uri: string = process.env.MONGODB_URI;
let client: MongoClient;
let clientPromise: Promise<MongoClient>;

if (process.env.NODE_ENV === "development") {
  // In development mode, use a global variable so that the value
  // is preserved across module reloads caused by HMR (Hot Module Replacement).

  let globalWithMongoClientPromise = global as typeof globalThis & {
    _mongoClientPromise: Promise<MongoClient>;
  };

  if (!globalWithMongoClientPromise._mongoClientPromise) {
    client = new MongoClient(uri);
    globalWithMongoClientPromise._mongoClientPromise = client.connect();
  }

  clientPromise = globalWithMongoClientPromise._mongoClientPromise;
} else {
  // In production mode, it's best to not use a global variable.
  client = new MongoClient(uri);
  clientPromise = client.connect();
}

// Export a module-scoped MongoClient promise. By doing this in a
// separate module, the client can be shared across functions.
export default clientPromise;