set a variable in express.js

    //Set a variable using Express.js
    const express = require('express');
    const app = express();
    const port = 3000;
    
    //Create a variable to store a string
    let myVariable = "This is my variable";
    
    //Set the variable using Express.js
    app.set('myVariable', myVariable);
    
    //Use the variable in an Express.js route
    app.get('/', (req, res) => {
      res.send(`My variable is: ${req.app.get('myVariable')}`);
    });
    
    app.listen(port, () => console.log(`Server running on port ${port}`));
  

To set a variable in Express.js, you can use the app.set() method. This method allows you to store a value in the Express.js application object, which is accessible from all routes. This can be useful for storing data that you need to access from multiple routes. In the example above, we first create a variable called myVariable and store a string inside it. Then, we use the app.set() method to store this variable in the Express.js application object. Finally, we use the req.app.get() method to access the variable in the route and use it to send a response to the client. You can also set multiple variables using the same app.set() method. Just provide multiple key-value pairs as arguments and Express.js will store them all in the application object.