[Resource] Validation Middleware

[Atlinx]

If anyone needs validation middleware for their fields that runs before a modifying operation, here's one I made:

validation.middleware.ts

This middleware listens for any operation that modifies an entity (update, create, or replace). Some caveats are that this isn't typed, because I'm not sure how to get generics working with something like this. It'll be easy to add types once we get shorthands #224 though.

Use

Single configuration

import { validationMiddleware } from 'validation.middleware';

const entityManager = new EntityManager({
  mongodb: {
    default: db,
  },
  middlewares: [
    validationMiddleware({
      userRole: { // Entity
        roleCode: [ // Field on entity
          async (newValue) => {
            console.log("I'm validating!");
            if (newValue !== "USER")
              return new Error("Role must be 'USER!'"); // Return an error if the validation failed. 
          },
          async (newValue) => {
            console.log("I'm validating again for roleCode!"); // Return nothing if the validation succeeds
          }
        ],
        userId: [
          async (newValue) => {
            
          }
        ]
      }
    })
  ],
});

Multiple options, merged together

import { validationMiddleware, mergeValidationOptions } from 'validation.middleware';

const optionsOne = {
  userRole: {
    roleCode: [
      async (newValue) => {
        if (newValue !== "USER")
          return new Error("Role must be 'USER!'"); // Return an error if the validation failed. 
      }
    ]
  }, 
};

const optionsTwo = {
  userRole: {
    roleCode: [
      async (newValue) => {
        if (newValue !== "ADMIN")
          return new Error("Role must be 'ADMIN!'"); // Return an error if the validation failed. 
      }
    ],
    userId: [
      async (newValue) => {
        console.log("I'm validating from userId!");
      }
    ]
  }
};

const entityManager = new EntityManager({
  mongodb: {
    default: db,
  },
  middlewares: [
    // Merges 2 or more options together.
    validationMiddleware(mergeValidationOptions(optionsOne, optionsTwo))
  ],
});

[edobrb]

When we add it to the default middlewares of typetta it will need some typing, but it looks cool!