How do you implement API documentation with Swagger/OpenAPI in Node.js?

Question

Accepted Answer

**Swagger/OpenAPI** — standard for API documentation.

```javascript
const swaggerJsdoc = require("swagger-jsdoc");
const swaggerUi = require("swagger-ui-express");

const options = {
    definition: {
        openapi: "3.0.0",
        info: {
            title: "My API",
            version: "1.0.0",
        },
        servers: [{ url: "http://localhost:3000" }],
    },
    apis: ["./routes/*.js"],
};

const swaggerSpec = swaggerJsdoc(options);
app.use("/api-docs", swaggerUi.serve, swaggerUi.setup(swaggerSpec));

// In route file
/**
 * @swagger
 * /users:
 *   get:
 *     summary: Get all users
 *     parameters:
 *       - in: query
 *         name: page
 *         schema:
 *           type: integer
 *     responses:
 *       200:
 *         description: List of users
 */
app.get("/users", getUsers);
```

**Swagger UI:**
- Interactive documentation.
- Try-it-out feature.
- Auto-generated from code.

Node.js: How do you implement API documentation with Swagger/OpenAPI in Node.js?