Middleware

Middleware is a function which has access to the request, response object. In the middleware, you can execute the code, or modify the response object. You can define one or more middlewares for a route.

Register route middleware using route.use() or route.error(). After validation, if it did not failed, all route.use() middleware will be executed in the order they are defined. The execution will stop if one of them calls res.end() or if an error is thrown in the middleware. On throw of error or on failure of validation, all the route.error() middleware will be executed in order, until one of them calls res.end().

Request and Response Object

Inside route.use().

import { route } from './route'

route.use((req, res) => {
    // Access the request object
    const method = req.method // string
    const path = req.path // string
    const params = req.params() // Record<string, any>
    const searchParam = req.searchParam() // Record<string, any>
    const searchParams = req.searchParams() // Record<string, any[]>
    const data = req.data // Record<string, any>
})

Update Response Object

You can update the response object by using res.next(). But be sure to return it. With res.next(), You can update status, statusText, headers, dataType, ctx and even data.

route.use((req, res) => {
    return res.next({
        ctx: {
            info: 'some info',
        }
        status: 200,
        statusText: 'OK',
        headers: {
            'Content-Type': 'text/plain',
        },
        dataType: 'json',
        data: 'Data',
    })
}).use((req, res) => {
    // Access the updated response object

    const ctx = res.ctx // { info: 'some info' }
    const status = res.status // 200
    const statusText = res.statusText // OK
    const headers = res.header() // { 'Content-Type': 'text/plain' }
    const dataType = res.dataType() // json
    const data = res.data() // 'Data'
})

End Response

Calling and returning res.end() in the middleware will stop the execution of any further middlewares and response will be sent. You don't always need to call res.end(), response will be sent eventually after all the middlewares are executed. You can modify the response object with it as well, except the ctx object. If you are sending data, you should set it in res.end() instead of res.next(), otherwise you will not get type inference for the data.

route.use((req, res) => {
    return res.end({
        data: 'Hello World',
        headers: {
            'Content-Type': 'text/plain'
        }
    })
})

Error Handling

route.error() is same as route.use(), it just has access to error along with request and response object. Request object is not validated in error handler.You can update the response object and terminate the execution the same way as in route.use().

route.error((error, req, res) => {

})