joi-type-extract

Clone of https://github.com/TCMiranda/joi-extract-type

Setup

1. Install package

   npm install @goodrequest/joi-type-extract
   or
   yarn add @goodrequest/joi-type-extract

2. Create ./src/types/joi/index.d.ts and import package in it, which will extend Joi types

   import '@goodrequest/joi-type-extract'

3. Add this compiler option and include created file in tsconfig.json in typeRoots

   {
       "compilerOptions": {
           "strictNullChecks": true,
           "typeRoots": [
               "./src/types"
           ]
       }
   }

Usage example

import Joi from 'joi'

export const requestSchema = () =>
    Joi.object({
        params: Joi.object({
            userID: Joi.number().required()
        }),
        query: Joi.object({
            search: Joi.string().required()
        }),
        body: Joi.object({
            name: Joi.string().required()
        })
    })

export const responseSchema = Joi.object({
   messages: Joi.array().items({
       message: Joi.string().required(),
       type: Joi.string().valid(MESSAGE_TYPE.SUCCESS).required()
   }).required()
})

type RequestType = Joi.extractType<ReturnType<typeof requestSchema>>
type ResponseType = Joi.extractType<typeof fullMessagesResponseSchema>

Extracted EequestType and ResponseType can be then used in express.Request and express.Response types

import { Request, Response, NextFunction } from 'express'

const businessLogic = async (
    req: Request<RequestType['params'], ResponseType, RequestType['body'], RequestType['query']>,
    res: Response<ResponseType>,
    next: NextFunction
) => {
    const { params, query, body } = req

    // params.userID will have number type
    // query.serch will have string type
    // body.name will have string type

    // response will be enforced to be same as ResponseType
    return res.json({
        messages: [
            {
                message: 'Response message',
                type: MESSAGE_TYPE.SUCCESS
            }
        ]
    })
}