middleware questions

Middleware functions in Express are functions that have access to the request, response, and the next middleware function in the application’s request-response cycle. Implement middleware by defining a function with `(req, res, next)` parameters and using `app.use(middlewareFunction)` to apply it globally or `router.use(middlewareFunction)` for specific routes. Middleware can perform tasks such as logging, authentication, or request modification.

Middleware in Redux provides a way to extend Redux's capabilities, allowing for side effects like API calls. For instance, 'redux-thunk' enables action creators to return functions instead of actions, facilitating asynchronous logic within your app.

Middleware functions process requests before they reach route handlers. They can modify `req` or `res`, end the request-response cycle, or pass control. For example: `app.use((req, res, next) => { console.log('Request received'); next(); });` logs every request.

Mongoose middlewares are functions that are executed at certain stages of a document's lifecycle. For example, you can define a pre-save hook: `userSchema.pre('save', function(next) { this.age = Math.abs(this.age); next(); });`. This executes before saving, allowing you to modify data. 
 
Explain pre and post hooks.