express-jdt-validator-middleware

An express middleware written in the style of and inspired by express-json-validator-middleware. This version is written in Typescript and employs JDT features of AJV to enable parsing of JSON schemas into full Typescript objects. You should be familiar with using JTD via AJV schemas first. For further information go the AJV Typescript page and the documentation for JDT schemas for AJV for further details about schema implementations. Please note that the JTD has not been completely approved yet.

Installation

Just run npm install to install.

Usage

First you need to import the middleware and AJV:

import AJV, {JTDSchemaType} from 'ajv/dist/jtd'
import {Validator, Options} from "express-jdt-validator-middleware";

Then you can create a new instance of the middleware in your express app, location will depend on how you've configured your proejct

//Code about using express goes here
const { validator } = new Validator(options);

When creating schemas use the Options type to make sure they are equivalent to the type you are parsing, if it is improperly constructed it will throw a compilation error.

interface BareUser{
    firstName: string;
    lastName: string;
}

class User implements BareUser {
    firstName: string;
    lastName: string;

    constructor(_firstName: string, _lastName: string) {
        this.firstName = _firstName;
        this.lastName = _lastName;
    }
}

const schema = {
    body: {
        value: new User("First", "Last"),
        schema: {
            properties: {
                firstName: {type: "string"},
                lastName: {type: "string"}
            }
        } as JTDSchemaType<User>
    }
}

const options: Option<typeof schema> = schema;

The formatting is defined as follows

const schema = {
    request property (eg. body/header): {
        value: some value of the target type (can be default), value is not used
        schema: This should match the structure of the object (parameters etc)
        } as JTDSchemaType<type of the value>
    }
}

Use for a route would look like the following

 app.post("/user", validate(options), (request, response) => {
    response.json({ success: true });
  });

Testing

Run npm install There are several testing modes since node-tap times out unless provided flags

Command	Description
test	Runs all tests with timeout possible
test-validator	Runs validation tests (does not run integration.test.ts) with timeout possible
test-integration	Runs integration tests (integration.test.ts) with timeout possible
test-debugger	Runs all tests with timeout disabled for debugging usage
test-validator-debugger	Runs validation tests (does not run integration.test.ts) with timeout disabled for debugging usage
test-integration-debugger	Runs integration tests (integration.test.ts) with timeout disabled for debugging usage