05 — Async seed with fetch

Goal

Add seedTodos — an async function that fetches three sample todos from a public API using Node's built-in global fetch (available since Node 18, so Node 26 already has it). No package installs needed.

The public API

JSONPlaceholder is a free, keyless, read-only REST API for testing. The endpoint:

https://jsonplaceholder.typicode.com/todos?_limit=3

returns an array like:

[
  { "userId": 1, "id": 1, "title": "delectus aut autem", "completed": false },
  { "userId": 1, "id": 2, "title": "quis ut nam facilis ...", "completed": false },
  { "userId": 1, "id": 3, "title": "fugiat veniam minus", "completed": false }
]

Add seedTodos

// todo.js — add below pendingTodos (Node 18+/26 has a global fetch)
async function seedTodos() {
  const res = await fetch(
    "https://jsonplaceholder.typicode.com/todos?_limit=3",
  );
  const data = await res.json();
  return data.map((d) => ({ text: d.title, done: d.completed }));
}

Two await calls:

1. await fetch(url) — waits for the HTTP response headers.
2. await res.json() — waits for the body to be fully read and parsed as JSON.

The .map reshapes each item to the todo shape { text, done } the rest of the module expects.

Updated module.exports

module.exports = {
  readTodos, writeTodos, addTodo, completeTodo, removeTodo, pendingTodos,
  seedTodos, formatList,
};

Checkpoint

node -e "require('./todo').seedTodos().then(t => console.log(t.length))"

Expected output: 3

(Requires a live internet connection. JSONPlaceholder is always available.)

How async/await works here

seedTodos is marked async, so it always returns a Promise. Callers use .then() or await to get the resolved value:

// .then() style (used in cli.js)
seedTodos().then((seeded) => {
  writeTodos(FILE, seeded);
  console.log(`Seeded ${seeded.length} todos`);
});

// await style (inside another async function)
const seeded = await seedTodos();

Both do the same thing; the CLI uses .then() so it doesn't need a top-level async wrapper.