Count the tasks

README.md

@@ -11,6 +11,7 @@ and in an adopter's first run. It is small on purpose, so a job is cheap and fas
 | GET | `/health` | Says the server is up |
 | GET | `/tasks` | Lists every task |
 | POST | `/tasks` | Adds a task, body `{"title": "..."}` |
+| GET | `/tasks/count` | Says how many tasks there are, and how many are done |
 | GET | `/tasks/:id` | Returns one task |
 | POST | `/tasks/:id/complete` | Marks a task done |
 | DELETE | `/tasks/:id` | Removes a task |

src/server.ts

@@ -7,6 +7,7 @@ import { TaskList, ValidationError } from './tasks.ts';
  *   GET    /health              is the server up
  *   GET    /tasks               every task
  *   POST   /tasks               add a task, body {"title": "..."}
+ *   GET    /tasks/count         how many tasks, and how many are done
  *   GET    /tasks/:id           one task
  *   POST   /tasks/:id/complete  mark a task done
  *   DELETE /tasks/:id           remove a task
@@ -35,6 +36,8 @@ async function handle(tasks: TaskList, request: IncomingMessage, response: Serve
     return send(response, 405, { error: 'method not allowed' });
   }
 
+  if (parts.length === 2 && parts[1] === 'count' && method === 'GET') return send(response, 200, tasks.count());
+
   const id = Number(parts[1]);
   if (!Number.isInteger(id) || id < 1) return send(response, 404, { error: 'not found' });
 

src/tasks.ts

@@ -36,4 +36,11 @@ export class TaskList {
   remove(id: number): boolean {
     return this.tasks.delete(id);
   }
+
+  /** How many tasks there are, and how many of them are done. */
+  count(): { total: number; done: number } {
+    let done = 0;
+    for (const task of this.tasks.values()) if (task.done) done++;
+    return { total: this.tasks.size, done };
+  }
 }

test/server.test.ts

@@ -40,6 +40,23 @@ describe('the HTTP API', () => {
     assert.equal((await call('GET', `/tasks/${id}`)).status, 404);
   });
 
+  it('counts the tasks, and the ones that are done', async () => {
+    const start = await call('GET', '/tasks/count');
+    assert.equal(start.status, 200);
+    const { total, done } = start.json as { total: number; done: number };
+
+    const first = (await call('POST', '/tasks', { title: 'Count me' })).json!.id as number;
+    const second = (await call('POST', '/tasks', { title: 'Count me too' })).json!.id as number;
+    assert.deepEqual(await call('GET', '/tasks/count'), { status: 200, json: { total: total + 2, done } });
+
+    await call('POST', `/tasks/${first}/complete`);
+    assert.deepEqual(await call('GET', '/tasks/count'), { status: 200, json: { total: total + 2, done: done + 1 } });
+
+    await call('DELETE', `/tasks/${first}`);
+    await call('DELETE', `/tasks/${second}`);
+    assert.deepEqual(await call('GET', '/tasks/count'), { status: 200, json: { total, done } });
+  });
+
   it('refuses a task without a title, and a body that is not JSON', async () => {
     assert.deepEqual(await call('POST', '/tasks', { title: '' }), { status: 400, json: { error: 'title must be text' } });
     assert.deepEqual(await call('POST', '/tasks', 'not json'), { status: 400, json: { error: 'the body must be JSON' } });

test/tasks.test.ts

@@ -33,4 +33,20 @@ describe('the task list', () => {
     assert.equal(tasks.remove(id), false);
     assert.equal(tasks.get(id), undefined);
   });
+
+  it('counts the tasks, and the ones that are done', () => {
+    const tasks = new TaskList();
+    assert.deepEqual(tasks.count(), { total: 0, done: 0 });
+
+    const { id } = tasks.add('Write the spec');
+    tasks.add('Review it');
+    tasks.add('Ship it');
+    assert.deepEqual(tasks.count(), { total: 3, done: 0 });
+
+    tasks.complete(id);
+    assert.deepEqual(tasks.count(), { total: 3, done: 1 });
+
+    tasks.remove(id);
+    assert.deepEqual(tasks.count(), { total: 2, done: 0 });
+  });
 });