ajv VS joi

One of the most basic applications of ReScript Schema is parsing - Accepting unknown JavaScript data, validating it, and returning the result of your desired type. There are dozens of such libraries, and the most popular ones are Zod, Valibot, Runtypes, Arktype, Typia, Superstruct, Effect Schema, and more. Also, even though this is slightly different, validation libraries like Ajv, Yup, and others also stand really close.

AJV for validating JSON responses from the speedtest cli

Tools like AJV (Another JSON Schema Validator) in JavaScript or the Python jsonschema library can help you validate JSON data against a schema.

Once your schema is ready, the AJV library can be used to apply it:

To simply validate a JSON Patch request body, the AJV library and a JSON schema can be used:

Speed and complete JSON schema compliance are the main priorities of AJV. Though it lacks the user-friendly APIs that Zod or VineJS has, it's great for validating JSON data, especially in APIs. But for tasks that require high efficiency, like validating huge JSON datasets, it's ideal.

To the article's point, many/most JavaScript projects are not optimised and better performance can be achieved with just JavaScript, and yes, JavaScript engines are becoming faster. However, no matter how much faster JavaScript can get, you can still always get faster with other system languages.

I work on high-performance stuff as a C++ engineer, currently working on an ultra fast JSON Schema validator. We are benchmarking against AJV (https://ajv.js.org), a project with a TON of VERY crazy optimisations to squeeze out as much performance as possible (REALLY well optimised compared to other JavaScript libraries), and we still get numbers like 200x faster than it with C++.

I'm not 100% sure, they most likely scraped the author emails of all NPM packages that (transitively) depend on ajv. Here's the GitHub issue from back then: https://github.com/ajv-validator/ajv/issues/1202

Ajv’s documentation is available here.

Package Feature Merit Demerit Link Zod TypeScript-first schema validation with static type inference Method chaining and easy to get ts type Newer package zod.dev joi This is almost same to zod Have many plugins Doesn't support static type inference https://github.com/sideway/joi Yup This is almost same to zod Have many plugins Missing some feature, function, deep object, promise... ... https://github.com/jquense/yup class-validator Validate class properties Have many features Code isn't clean https://github.com/typestack/class-validator ajv Validate by json scheme Enable to share schem to other languages Not supported typescript https://ajv.js.org/

Using Joi, a data validator for JavaScript.

See how I've used joi for validating the request body. You can install and use different libraries like this inside the helpers/routes. Joi can be installed with the following command:

3. joi

⭐ Recommended: Doing this manually is a ton of work, and if you're dealing with unknown objects often it would be better to lean onto a validation library to simplify it. My personal favorite is superstruct, although lots of people like joi or zod. They all do the same thing

The class-validator / class-transform looks really nice for formatting/validation but there is also joi. suretype is attractive since theoretically typeconv could generate jsonSchema for json-schema-faker and Open API docs.

Since Typescript is just a language and not a library of some sorts, it doesn't add runtime functionality. If this is what you're after, there's so many libraries that help converting unknown's into known types - joi, yup, superstruct (my choice), purify-ts Codec, io-ts

What does this library provide that is not provided by Yup, Zod, Superstruct (a personal favorite), Joi, Nope, computed-types, typanion, and all the other validation libraries?

True, I remember there's Yup and joi for JavaScript