express-decorator-validation

Decorator based validation for use in Express routes.

Getting started

Install the dependency.

npm install --save express-decorator-validation

Your tsconfig.json will need this configuration below:

{
  "compilerOptions": {
    "emitDecoratorMetadata": true,  // add this
    "experimentalDecorators": true, // add this
  }
}

Up the Express server and definig routes:

import { Validator } from 'express-decorator-validation';
import { PaginationRequestModel, CreateStudentModel } from './models';

import * as express from 'express';
import * as cors from 'cors';

const app = express();
app.use([express.json(), cors()]);

class StudentController 
{
    @Validator.query(PaginationRequestModel) // Model described below...
    static getStudents(request, response)
    {
        // You CAN TRUST in this request input now.
        const {page, page_size, search} = request.query;

        response.json({
            page, 
            page_size, 
            total: 1, 
            items: [
                {
                    name         : 'Peter',
                    last_name    : 'Parker',
                    date_of_birth: '1990-04-23',
                }
            ]
        });
    }

    @Validator.body(CreateStudentModel)  // Model described below...
    static createStudent(request, response)
    {
        // You CAN TRUST in this request input now.
        const { name, last_name, date_of_birth } = request.body;

        response.json({name, last_name, date_of_birth});
    }
}

app.get('/students', StudentController.getStudents);
app.post('/students', StudentController.createStudent);

app.listen(3000, () => console.log(`app is listening`));

Defining models:

npm install --save class-transformer class-validator reflect-metadata

import 'reflect-metadata';

import {
    IsInt,
    IsNumber,
    IsObject,
    IsOptional,
    IsString,
    Matches,
    Max,
    Min,
    MinLength,
    ValidateNested 
} from 'class-validator';

import { Type } from 'class-transformer';

export class CreditCardModel 
{
    @IsString()
    @MinLength(4)
    brand: string;

    @IsString()
    @MinLength(10)
    token: string;
}

export class CreateStudentModel 
{
    @MinLength(3)
    @IsString()
    name: string;

    @MinLength(3)
    @IsString()
    last_name: string;

    @IsOptional()
    @Matches(/^\d{4}-\d{2}-\d{2}$/, { message: 'Date of birth must mach with the format: YYYY-MM-DD' })
    date_of_birth?: string;

    @IsObject()
    @Type(() => CreditCardModel)
    @ValidateNested()
    creditcard: CreditCardModel;
}

export class PaginationRequestModel 
{
    @IsInt()
    @Min(1)
    @Type(() => Number)
    page: number;

    @Min(5)
    @Max(50)
    @Type(() => Number)
    page_size: number;

    @IsOptional()
    search?: string;
}

MIT License

Copyright (c) 2023 Leonardo Thibes

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the 'Software'), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.