What's the difference between version and constraints.version in routes options?

[ligreman]

I'm learning Fastify and now I'm trying the api versioning feature. In the docs there are two options for the routes that seems the same thing to me:

• version: a semver compatible string that defined the version of the endpoint. Example.

• constraints: defines route restrictions based on request properties or values, enabling customized matching using find-my-way constraints. Includes built-in version and host constraints, with support for custom constraint strategies.

https://fastify.dev/docs/latest/Reference/Routes/#routes-options

The example in the "version" one even redirects to the constraints section of the docs. Are these options the same? is version a shortcut of constraints.version?

I've tested both and aparently do the same thing... what's the difference doing:
fastify.route({ method: 'GET', url: '/foo', constraints: {version: '1.1.0'} });
and
fastify.route({ method: 'GET', url: '/foo', version: '1.1.0' });

Thanks!

[metcoder95]

They are the same, and internally the version property is added as constraints.version if passed while adding the route.
This is currently under a deprecation notice and most likely will be drop in the next major. Its recommended to use constraints: { version: 'x.x.x' } instead