WIP: Supercrud

WIP: A small, opinionated library to generate functional, testable, and readable CRUD handlers for your database models. Works with any ORM or even raw SQL code as you specify how to create, read, update and delete your models. Can be used with any web framework.

Context

Writing route handlers for web applications in Node.js

Problem

You find yourself writing almost identical CRUD handlers for all your database models. This includes input-checking, validation, how the model gets created/read/updated/deleted, and the formatted response to the user. The code imperative and may require some effort to understand for new developers.

Without Supercrud

// Route handler to create a new user in Express
app.post('/user', (req, res) => {
  if(req.body.username && req.body.password){
    new UserModel({username: req.body.username, password: req.body.password})
      .save()
      .then(savedUser => {
        res.send({message: 'User saved.', data: savedUser});
      });
  } 
  else {
    // Handle missing field(s)
  }
})

app.post('/article', addUsernameToRequest, (req, res) => {
  if(req.body.title && req.body.text){
    new ArticleModel({title: req.body.title, text: req.body.text, created_by: req.username })
      .save()
      .then(savedArticle => {
        res.send({message: 'Article saved.', data: savedArticle});
      });
  } 
  else {
    // Handle missing field(s)
  }
})

With Supercrud

// 1. Define your save function. (See other examples for update, deleted and get functions.)
// This is done only once and will work for all of your models assuming they have the same methods.
// You may export the CRUD object if you like to manage distinct models in seperate files.

import Supercrud from 'supercrud';

const CRUD = Supercrud({
  saveFunction: (generalModel, body) => new generalModel(body).save()
  // Other functions: updateFunction, getFunction, deleteFunction
});


// 2. Create your handlers. The returned handlers will call your saveFunction.

const userHandler = CRUD.create(UserModel, {
  requiredFields: ['username', 'password'],
  after: savedUser => ({ message: 'User saved.', data: savedUser})
})

const articleHandler = CRUD.create(ArticleModel, {
  requiredFields: ['title', 'text'],
  allowedFields: ['title', 'text'],
  before: (body, request) => Object.assign({}, body, { created_by: req.username }),
  after: savedUser => ({ message: 'User saved.', data: savedUser})
})

// 3. Hook it up to Express, Restify or whatever web framework you use.

app.post('/user', (req, res) => {
  userHandler(req.body).then(response => res.send(response))
})
app.post('/article', addUsernameToRequest, (req, res) => {
  articleHandler(req.body).then(response => res.send(response))
})

or with async await

app.post('/user', async (req, res) => res.send(await userHandler(req.body))
app.post('/article', addUsernameToRequest, async (req, res) => res.send(await articleHandler(req.body))

Benefits of Supercrud

Supecrud aims to make your code more readable and reduce boilerplate. In addition, since we are seperating the logic of the handlers into smaller functions (before, after) without side-effects, we can easily write good unit tests to verify the correctness of the code.