ObjectSchema.extend Does not return a schema instance

[esatterwhite]

Prerequisites

• [X] I have written a descriptive issue title
• [X] I have searched existing issues to ensure the bug has not already been reported

Fastify version

4.x.x

Plugin version

4.2.1

Node.js version

18.0

Operating system

Linux

Operating system version (i.e. 20.04, 11.3, 10)

Manjaro 5.10.218 x86

Description

Once you call extend on a schema, the function chain is broken because the extend function returns a plain object rather than an instance of the schema being extended. This breaks the normal usage of the builder pattern implemented by this library.

Link to code that reproduces the bug

https://github.com/fastify/fluent-json-schema/blob/6db9f0ba5bbf49aa266bc44dfb82a8f0c04b7c71/src/ObjectSchema.js#L350

Expected Behavior

One should be able to continue chaining function calls such as without or only, etc after calling extend.

It should be safe to use the schema factory function found on the schema to build out a new instance of the same type.

[mcollina]

Thanks for reporting!

Can you provide steps to reproduce? We often need a reproducible example, e.g. some code that allows someone else to recreate your problem by just copying and pasting it. If it involves more than a couple of different file, create a new repository on GitHub and add a link to that.

[esatterwhite]

var fluent = require('fluent-json-schema')
var base = fluent
  .object()
  .prop('one', fluent.number())
  .prop('two', fluent.number())

var extended = fluent.object()
  .prop('three', fluent.number())
  .prop('four', fluent.number())
  .extend(base)

var alternate = extended.without(['one'])

var alternate = extended.without(['one'])
                         ^

TypeError: extended.without is not a function
    at Object.<anonymous> (/home/esatterwhite/dev/js/logdna/auth-provider-service/error.js:12:26)
    at Module._compile (node:internal/modules/cjs/loader:1369:14)
    at Module._extensions..js (node:internal/modules/cjs/loader:1427:10)
    at Module.load (node:internal/modules/cjs/loader:1206:32)
    at Module._load (node:internal/modules/cjs/loader:1022:12)
    at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:135:12)
    at node:internal/main/run_main_module:28:49

Node.js v20.12.2

[mcollina]

Thanks for reporting! Would you like to send a Pull Request to address this issue? Remember to add unit tests.