How I can use " LIKE " operator on?

In Mongoose, there is no direct "LIKE" operator because it is primarily derived from SQL concepts. Instead, Mongoose uses regular expressions within the MongoDB context to achieve similar functionality. When performing a query analogous to SQL's LIKE operation, you use regular expressions to match patterns within the field.

For example, suppose you have a user model (User Model) and you want to find all users whose usernames contain a specific string. You can use regular expressions as shown below:

javascript
const mongoose = require('mongoose');
const User = mongoose.model('User', new mongoose.Schema({ username: String }));

const searchString = 'john';
User.find({ username: new RegExp(searchString, 'i') }, function(err, users) {
  if (err) throw err;
  console.log(users); // This prints all users whose usernames contain 'john', case-insensitive
});

In the above code, we create a regular expression new RegExp(searchString, 'i'), where searchString is the string to search for (here, 'john'), and 'i' is a flag indicating case-insensitive matching.

This regular expression treats any value containing searchString as a match, similar to SQL's LIKE '%john%' operation. If you want to match text starting or ending with searchString, you need to slightly modify the regular expression:

• For prefix matching: '^john' (equivalent to LIKE 'john%')
• For suffix matching: /john$ (equivalent to LIKE '%john')

Using Mongoose, regular expressions provide significant flexibility, but you must have a basic understanding of JavaScript regular expressions.