AdonisJS custom validation rule for disallowing emojis

01_contracts_validator.ts

// Save inside contracts/validator.ts

declare module '@ioc:Adonis/Core/Validator' {
  interface Rules {
    disallowEmoji(): Rule
  }
}

02_validator.ts

// Save inside start/validator.ts

import { validator } from '@ioc:Adonis/Core/Validator'

validator.rule(
  'disallowEmoji',
  (value, {}, { pointer, arrayExpressionPointer, errorReporter }) => {
    if (typeof value !== 'string') {
      return
    }

    if (/<% RGI_Emoji %>|\p{Emoji_Presentation}|\p{Emoji}\uFE0F|\p{Emoji_Modifier_Base}/gu.test(value)) {
      errorReporter.report(
        pointer,
        'disallowEmoji',
        'Emojis are not allowed',
        arrayExpressionPointer
      )
    }
  }
)

03_SomeController.ts

const { password } = await request.validate({
  schema: schema.create({
    password: schema.string({ trim: true }, [
      rules.minLength(8),
      rules.maxLength(28),
      rules.confirmed(),
      rules.disallowEmoji(),
    ]),
  }),
})