koa.md

koa intergration

ajv is used to do actual validation

here's what we will achieve in the end

import { str } from 'kontur'
import { schema } from './schema'

router.post('/', schema({
    name: str.minlen(3),
    description: str.optional
}), async (ctx) => {
    await ctx.db.thing.insert(ctx.reqeust.body)
    ctx.status = 201
})

get ajv and kontur

yarn add kontur ajv@^5.0.0-beta

write the middleware

strict is used here so that unexpected properties won't be presented in request body

minsize(1) prevent empty request body when all properties are optional

import Ajv from 'ajv'
import { compile, object } from 'kontur'

const ajv = new Ajv()

export const schema = schema => {
  let validate = ajv.compile(compile(object.strict.minsize(1).properties(schema)))
  return async (ctx, next) => {
    if (!validate(ctx.request.body)) {
      ctx.status = 400
      ctx.body = validate.errors
    } else {
      await next()
    }
  }
}