Examples

Practical examples for @powerduck/openapi-codegen. All examples assume a parsed OpenAPI document object named document.

1. JavaScript fetch

import { generate } from "@powerduck/openapi-codegen";

const code = generate({
  document,
  path: "/pets/{id}",
  method: "get",
  language: "javascript",
  client: "fetch",
});

console.log(code);

Other JavaScript clients: axios, ofetch, jquery, xhr. For server-side Node equivalents, use node/fetch, node/axios, node/ofetch, or node/undici.

2. Python requests

const code = generate({
  document,
  path: "/pets",
  method: "post",
  language: "python",
  client: "requests",
});

console.log(code);

Other Python clients: aiohttp, http-client, httpx-sync, httpx-async.

3. cURL (shell)

const code = generate({
  document,
  path: "/pets/{id}",
  method: "get",
  language: "shell",
  client: "curl",
  serverUrl: "https://staging.example.com/v1",
  securityValues: { bearerAuth: "YOUR_ACCESS_TOKEN" },
});

console.log(code);

Other shell clients: wget and httpie. For multipart/form-data uploads, prefer shell/curl or shell/httpie over shell/wget.

4. Discover and pick a generator

Use list() to discover what is available, then generate with the chosen pair:

import { generate, list } from "@powerduck/openapi-codegen";

const all = list();
console.log(all.length, "generators available");

const picked = all.find(
  (g) => g.language === "python" && g.client === "requests",
);

if (!picked) throw new Error("generator unavailable");

const code = generate({
  document,
  path: "/pets",
  method: "get",
  language: picked.language,
  client: picked.client,
});

5. Register a custom generator

Implement the Generator interface and call register:

import { register, generate } from "@powerduck/openapi-codegen";
import type { RequestIR } from "@powerduck/openapi-codegen";

register({
  language: "mylang",
  client: "my-client",
  generate(request: RequestIR): string {
    return [
      `// ${request.method} ${request.baseUrl}${request.path}`,
      `mylang.request(${JSON.stringify({
        method: request.method,
        url: request.baseUrl + request.path,
      })})`,
    ].join("\n");
  },
});

const code = generate({
  document,
  path: "/pets",
  method: "get",
  language: "mylang",
  client: "my-client",
});

console.log(code);

6. Use a plugin

A plugin bundles one or more generator registrations through use():

import { use, generate } from "@powerduck/openapi-codegen";

use({
  name: "internal-generators",
  register(api) {
    api.register({
      language: "go",
      client: "our-wrapper",
      generate(request) {
        return `// go wrapper for ${request.method} ${request.path}`;
      },
    });
    api.register({
      language: "ruby",
      client: "our-wrapper",
      generate(request) {
        return `# ruby wrapper for ${request.method} ${request.path}`;
      },
    });
  },
});

const code = generate({
  document,
  path: "/pets",
  method: "get",
  language: "go",
  client: "our-wrapper",
});

7. Generate from a direct RequestIR

Skip normalize entirely by building a RequestIR yourself:

import { generate } from "@powerduck/openapi-codegen";
import type { RequestIR } from "@powerduck/openapi-codegen";

const request: RequestIR = {
  method: "GET",
  baseUrl: "https://api.example.com",
  path: "/users/{id}",
  parameters: [
    { name: "id", in: "path", value: 123 },
    { name: "limit", in: "query", value: 10, style: "form", explode: true },
  ],
  headers: [
    { name: "Accept", in: "header", value: "application/json" },
  ],
  body: undefined,
  security: [
    { name: "bearerAuth", type: "http", scheme: "bearer", value: "token-abc" },
  ],
};

const code = generate({
  request,
  language: "javascript",
  client: "fetch",
});

console.log(code);

8. Error handling

generate() throws for missing input, unknown generators, and unresolved references. Always wrap when processing untrusted input:

try {
  const code = generate({
    document,
    path: "/does-not-exist",
    method: "get",
    language: "javascript",
    client: "fetch",
  });
  console.log(code);
} catch (error) {
  console.error("Failed:", error instanceof Error ? error.message : error);
}

Expected error messages include Unsupported generator: ... and Path not found: ... / Operation not found: METHOD /path.

9. Soft $ref mode

When a document may contain broken or circular references, pass softRefMode: true so resolution degrades gracefully instead of throwing:

const code = generate({
  document,
  path: "/pets/{id}",
  method: "get",
  language: "python",
  client: "requests",
  softRefMode: true,
});