Mocking the API

Before we connect a real database, it’s often helpful to build “mocked” endpoints. This allows frontend developers to start working immediately and helps us define our API contract.

The Task Resource

For our Task Manager, a Task looks like this:

interface Task {
  id: string;
  title: string;
  description?: string;
  status: "todo" | "in_progress" | "completed";
  createdAt: Date;
}

Creating Mock Data

Let’s create a simple in-memory array to store our tasks.

src/index.ts

let tasks = [
  {
    id: "1",
    title: "Learn Hono",
    description: "Read the documentation",
    status: "in_progress",
    createdAt: new Date(),
  },
  {
    id: "2",
    title: "Build API",
    status: "todo",
    createdAt: new Date(),
  },
];

Implementing Endpoints

We will implement the standard CRUD (Create, Read, Update, Delete) operations.

1. Get All Tasks

app.get("/api/tasks", (c) => {
  return c.json({ tasks });
});

2. Get Single Task

app.get("/api/tasks/:id", (c) => {
  const id = c.req.param("id");
  const task = tasks.find((t) => t.id === id);

  if (!task) {
    return c.json({ error: "Task not found" }, 404);
  }

  return c.json({ task });
});

3. Create Task

app.post("/api/tasks", async (c) => {
  const body = await c.req.json();

  const newTask = {
    id: String(tasks.length + 1),
    title: body.title,
    description: body.description,
    status: "todo",
    createdAt: new Date(),
  };

  tasks.push(newTask);
  return c.json({ task: newTask }, 201);
});

Note: In a real app, we would validate the input body using Zod.

Why Mocking Matters

1. Speed: You don’t need to set up a database to start coding.
2. Contract First: It forces you to think about the JSON structure.
3. Frontend Unblocking: The frontend team can build the UI against these endpoints while the backend team works on the database integration.

In the next section, we will learn how to test these endpoints using Postman.