Codegen

SPFN automatically generates type-safe API clients from your route definitions. The codegen system analyzes your defineRouter configuration and produces client code with full type inference.

Setup

Configure Generator

Create a codegen.config.ts at the project root:

typescript
// codegen.config.ts
import { defineConfig } from '@spfn/core/codegen';

export default defineConfig({
    generators: [
        {
            name: 'api-client',
            output: './src/client/api.ts',
            router: './src/server/server.config.ts',
        },
    ],
});

CLI Commands

Terminal
# Generate API client
pnpm spfn codegen run

# Run specific generator
pnpm spfn codegen run --name api-client

# List registered generators
pnpm spfn codegen list

# Watch mode (included in dev server)
pnpm spfn:dev

Generated Client

The codegen produces a typed API client file:

typescript
// src/client/api.ts (generated)
import { createApi } from '@spfn/core/nextjs';
import type { AppRouter } from '@/server/server.config';

export const api = createApi<AppRouter>();

Usage

typescript
import { api } from '@/client/api';

// Type-safe API calls
const user = await api.getUser.call({
    params: { id: '123' },
});

const users = await api.getUsers.call({
    query: { page: 1, limit: 20 },
});

const created = await api.createUser.call({
    body: { email: 'user@example.com', name: 'User' },
});

Custom Generators

For advanced use cases, define custom generators using defineGenerator:

typescript
import { defineGenerator } from '@spfn/core/codegen';

const myGenerator = defineGenerator({
    name: 'my-package:generator',
    // ... custom generator configuration
});

For a complete guide on building custom generators, see Custom Generators.

Related

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