Category: JavaScript

Sometimes, we want to fix the "cannot find module ‘mongodb’" error with Node.js.

In this article, we’ll look at how to fix the "cannot find module ‘mongodb’" error with Node.js.

How to fix the "cannot find module ‘mongodb’" error with Node.js?

To fix the "cannot find module ‘mongodb’" error with Node.js, we should install the mongodb module.

To install it globally, we run

npm install mongodb -g 

We can also install it locally by running

npm install mongodb 

after going into our Node.js project folder.

Conclusion

To fix the "cannot find module ‘mongodb’" error with Node.js, we should install the mongodb module.

Sometimes, we want to create a secure (TLS/SSL) Websocket server with Node.js

In this article, we’ll look at how to create a secure (TLS/SSL) Websocket server with Node.js.

How to create a secure (TLS/SSL) Websocket server with Node.js?

To create a secure (TLS/SSL) Websocket server with Node.js, we can use the https module.

For instance, we write

const WebSocket = require("ws").Server;
const { createServer } = require("https");
const fs = require("fs");

const server = createServer({
  cert: fs.readFileSync(config.sslCertPpath),
  key: fs.readFileSync(config.ssKeyPpath),
});
const socket = new WebSocket({
  server,
});

socket.on(() => {
  //...
});
server.listen(config.port);

to call createServer to create a HTTPS server with the cert and key certificate and key files.

Then we use the WebSocket constructor to create a WebSocket server from the HTTPS server.

Next, we call socket.on to listen for communication.

And we call server.listen to start the server.

Conclusion

To create a secure (TLS/SSL) Websocket server with Node.js, we can use the https module.

Sometimes, we want to create an AWS Lambda function to write to S3with Node.js.

In this article, we’ll look at how to create an AWS Lambda function to write to S3with Node.js.

How to create an AWS Lambda function to write to S3with Node.js?

To create an AWS Lambda function to write to S3with Node.js, we can call putObject.

For instance, we write

var AWS = require("aws-sdk");
const putObjectToS3 = (bucket, key, data) => {
  const s3 = new AWS.S3();
  const params = {
    Bucket: bucket,
    Key: key,
    Body: data,
  };
  s3.putObject(params, (err, data) => {
    //...
  });
};

to create the putObjectToS3 function.

In it, we call s3.putObject with the info in the params object to push our file, which is stored in data, to the location with the given bucket and key.

Conclusion

To create an AWS Lambda function to write to S3with Node.js, we can call putObject.

Sometimes, we want to launch a browser from the a Node.js command line script.

In this article, we’ll look at how to launch a browser from the a Node.js command line script.

How to launch a browser from the a Node.js command line script?

To launch a browser from the a Node.js command line script, we can use the open package.

To install it, we run

npm install --save open

Then we use it by writing

const open = require("open");

(async () => {
  await open("unicorn.png", { wait: true });
  await open("https://example.com");
  await open("https://example.com", { app: "firefox" });
  await open("https://example.com", {
    app: ["google chrome", "--incognito"],
  });
})();

to call open with a file path with

await open("unicorn.png", { wait: true });

We set wait to true to wait for the file to open.

Also, we can call it with a URL with

await open("https://sindresorhus.com");

to open the browser with the URL.

We specify the app option to set the program to open.

Also, we can pass in command line arguments for the app being opened with

await open("https://sindresorhus.com", {
  app: ["google chrome", "--incognito"],
});

Conclusion

To launch a browser from the a Node.js command line script, we can use the open package.

Sometimes, we want to wait for all images to load then take screenshot with Puppeteer.

In this article, we’ll look at how to wait for all images to load then take screenshot with Puppeteer.

How to wait for all images to load then take screenshot with Puppeteer?

To wait for all images to load then take screenshot with Puppeteer, we can use the waitUntil option with the page.goto method.

For instance, we write

await page.goto("https://www.example.com/", { waitUntil: "networkidle0" });

to go to https://www.example.com/ with goto and set the waitUntil option to 'networkidle0' to wait for everything to finish loading before resolving the returned promise.

Conclusion

To wait for all images to load then take screenshot with Puppeteer, we can use the waitUntil option with the page.goto method.