Using ArkType with @google/genai

import { GoogleGenAI } from '@google/genai'
import { config } from '$/config'
import { toGeminiSchema } from './utils'
import { type, type Type } from 'arktype'

const genAI = new GoogleGenAI({ apiKey: config.apiKeys.google })

/**
 * Generates a reponse as JSON data constrained to an Arktype schema.
 */
export async function generateJsonContent<t extends type>({
  text,
  prompt,
  schema,
}: {
  text: string
  prompt: string
  schema: t
}): Promise<t['infer'] | undefined> {
  const response = await genAI.models.generateContent({
    model: config.models.generate,
    contents: `User input: ${text}
    Assistant:`,
    config: {
      systemInstruction: prompt,
      responseMimeType: 'application/json',
      responseJsonSchema: toGeminiSchema(schema),
    },
  })

  const data = parseJsonString.to(schema as type.cast<t['t']>)(response.text)
  if (data instanceof type.errors) {
    console.error(new Error('GoogleGenAI returned an invalid JSON response', { cause: data }))
    return
  }

  return data
}

const data = await generateJsonContent({
  text: 'hello',
  prompt: 'You are a helpful assistant',
  schema: type({ a: 'string', b: 'number' }),
}) // { a: string; b: number }