Category: JavaScript

Sometimes, we want to fix the "’nodemon’ is not recognized as an internal or external command, program or batch file." error in Windows.

In this article, we’ll look at how to fix the "’nodemon’ is not recognized as an internal or external command, program or batch file." error in Windows.

How to fix the "’nodemon’ is not recognized as an internal or external command, program or batch file." error in Windows?

To fix the "’nodemon’ is not recognized as an internal or external command, program or batch file." error in Windows, we can install nodemon as a dev dependency in our Node.js project.

To do this, we go to our Node project folder and run

npm install --save-dev nodemon

Then in package.json we add

{
  //...
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1",
    "nodemon": "./node_modules/.bin/nodemon"
  }
  //...
}

to add the nodemon script that runs nodemon.

Then we can run the nodemon script by running

npm run nodemon

Conclusion

To fix the "’nodemon’ is not recognized as an internal or external command, program or batch file." error in Windows, we can install nodemon as a dev dependency in our Node.js project.

Sometimes, we want to fix the "’node’ is not recognized as an internal or external command" error in Windows.

In this article, we’ll look at how to fix the "’node’ is not recognized as an internal or external command" error in Windows.

How to fix the "’node’ is not recognized as an internal or external command" error in Windows?

To fix the "’node’ is not recognized as an internal or external command" error in Windows, we can add the Node.js executable path to the PATH environment variable.

To do this, we run

SET PATH=C:\Program Files\Nodejs;%PATH%

to add C:\Program Files\Nodejs directory to the PATH as another entry in the list of values.

Conclusion

To fix the "’node’ is not recognized as an internal or external command" error in Windows, we can add the Node.js executable path to the PATH environment variable.

Sometimes, we want to get the Socket.IO connected user count.

In this article, we’ll look at how to get the Socket.IO connected user count.

How to get the Socket.IO connected user count?

To get the Socket.IO connected user count, we can use the socketIO.engine.clientsCount property.

We can also use

io.sockets.sockets.length

or

Object.keys(io.sockets.connected).length

to get the connected user count.

Conclusion

To get the Socket.IO connected user count, we can use the socketIO.engine.clientsCount property.

Sometimes, we want to validate email syntax with Mongoose.

In this article, we’ll look at how to validate email syntax with Mongoose.

How to validate email syntax with Mongoose?

To validate email syntax with Mongoose, we can set the match property to an array with the regex to validate against and validation error message.

For instance, we write

const validateEmail = (email) => {
  const re = /^\w+([\.-]?\w+)*@\w+([\.-]?\w+)*(\.\w{2,3})+$/;
  return re.test(email);
};

const EmailSchema = new Schema({
  email: {
    type: String,
    trim: true,
    lowercase: true,
    unique: true,
    required: "Email address is required",
    validate: [validateEmail, "Please fill a valid email address"],
    match: [
      /^\w+([\.-]?\w+)*@\w+([\.-]?\w+)*(\.\w{2,3})+$/,
      "Please fill a valid email address",
    ],
  },
});

to create the EmailSchema with the email field.

we add the validate option set to an array with the validateEmail function to validate the email string against the re regex and a validation error message if validateEmail returns false.

Likewise, we set match to an array with the regex to validate against and an validation error message.

We’ll get the message when we call save with an invalid email valuein thesave` callback.

Conclusion

To validate email syntax with Mongoose, we can set the match property to an array with the regex to validate against and validation error message.

Sometimes, we want to bind Express.js to a specific IP address.

In this article, we’ll look at how to bind Express.js to a specific IP address.

How to bind Express.js to a specific IP address?

To bind Express.js to a specific IP address, we call listen with the IP address as the 2nd argument.

For instance, we write

const server = app.listen(3000, "127.0.0.1", onServerListening);

to call app.listen with the port, IP address string, and the onServerListening callback function that runs when the server is started.

This will bind the Express app to 127.0.0.1

Conclusion

To bind Express.js to a specific IP address, we call listen with the IP address as the 2nd argument.