swaggerValidation.ts

import * as Ajv from 'ajv';
import swaggerDefinition from './my-swagger-definition';
import { Request, Response, NextFunction } from 'express';

const ajv = Ajv({ allErrors: true });

// validation middleware
const validateSchema = (schema: UserResSchema) => {
  return (req: Request, res: Response, next: NextFunction) => {

    const valid = ajv.validate(schema, req.body); // return boolean

    if (!valid) {
      res.send(new Error('Could not validate schema ' + schema.title));
    }

    next()
  }
}

app.post('/users', validateSchema(swaggerDefinition.definitions.UserRes.schema), (req: Request, res: Response) => {
  res.send(req.body).status(201).end();
});