feat(validator): Introduce responseValidator

[EdamAme-x]

Resolve: #2439
Related: honojs/middleware#184

This is proposal.
It has not been tested, nor is it fully molded.

import { Hono } from '../preset/quick'
import { responseValidator } from '.'

const app = new Hono()

app
  .use(
    '*',
    responseValidator('text', (value, c) => {
      if (!/\d/.test(value)) {
        return c.text('Invalid!', 400)
      }
    })
  )
  .get('/', (c) => {
    return c.text(c.validate('hello world at ' + Date.now()))
  })
  .get('/invalid', (c) => {
    return c.text(c.validate('hello world at ' + NaN))
  })

export default app

The data is kept intact in the context.

The author should do the following, if applicable

No Prepared

• Add tests
• Run tests
• bun run format:fix && bun run lint:fix to format the code
• Add TSDoc/JSDoc to document the code

[EdamAme-x]

What do you think about this API? @yusukebe

[EdamAme-x]

The only code added to context is the following, with no major changes to the bundle size.
this.validate=a=>(this.validateData=a,a);

[codecov]

Codecov Report

Attention: Patch coverage is 8.60215% with 85 lines in your changes missing coverage. Please review.

Project coverage is 90.57%. Comparing base (ac4d42c) to head (6b87b95).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
src/validator/response-validator.ts	7.81%	59 Missing ⚠️
src/validator/response-validator.sandbox.ts	0.00%	24 Missing ⚠️
src/context.ts	60.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3843      +/-   ##
==========================================
- Coverage   91.31%   90.57%   -0.75%     
==========================================
  Files         161      163       +2     
  Lines       10240    10333      +93     
  Branches     2999     2889     -110     
==========================================
+ Hits         9351     9359       +8     
- Misses        888      973      +85     
  Partials        1        1              

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[EdamAme-x]

In the future, it may be necessary to properly infer the output type for RPC.

[belgattitude]

@EdamAme-x just bringing to your attention that there's an initiative of a standard schema specification that seems to be implemented in latest zod, valibot beta, arktypes...

I don't know if it affects your PR but in case it might be good to have a look.

BTW I'm just starting some internal projects with hono and nextjs and it looks great !

[EdamAme-x]

@belgattitude
Thanks for letting us know!

There is already an interesting discussion about standard schema in the honojs/middleware repository, if you want to check it out!