Day 1 · The Simplest Thing — Alice in Userland

Story

Alice is a developer, and developers have a lot of todos. Fix this, try that, answer an old message. She wants to keep them all in one place on her computer: write a todo down, see all of them together, and mark one as done when she finishes it.

This is only a side project, so she does not want complicated code. She takes the smallest step she can think of. She writes one file, main.ts, and puts everything in it. She runs it with bun main.ts, because Bun reads TypeScript on its own. There is nothing to build and nothing to set up. She adds no libraries and no database. Each todo becomes a small file in ~/.todos, a folder in her home. She keeps it there and not next to her code, because she has one todo list and she wants to see it from wherever she is standing. It is a plain folder, so she can open it and read her todos with her own eyes. It works, and today that is enough.

Alice's Notebook

Nothing written down on this day.

Files

1

Choose a file from the tree.

import { existsSync, mkdirSync, readdirSync, readFileSync, writeFileSync, rmSync } from "node:fs";
import { homedir } from "node:os";
import { join } from "node:path";

type Todo = {
  id: string;
  title: string;
  done: boolean;
  createdAt: string;
};

const dir = join(homedir(), ".todos");
if (!existsSync(dir)) mkdirSync(dir);

const [command, ...rest] = process.argv.slice(2);

switch (command) {
  case "add": {
    const title = rest.join(" ").trim();

    if (title === "") {
      console.error("a todo needs a title");
      process.exitCode = 1;
      break;
    }

    const todo: Todo = {
      id: Date.now().toString(36),
      title,
      done: false,
      createdAt: new Date().toISOString(),
    };

    writeFileSync(join(dir, `${todo.id}.json`), JSON.stringify(todo, null, 2) + "\n");

    console.log(`added ${todo.id}  ${todo.title}`);
    break;
  }

  case "list": {
    const todos: Todo[] = readdirSync(dir)
      .filter((file) => file.endsWith(".json"))
      .map((file) => JSON.parse(readFileSync(join(dir, file), "utf8")));

    todos.sort((a, b) => a.createdAt.localeCompare(b.createdAt));

    if (todos.length === 0) {
      console.log("nothing to do");
      break;
    }

    for (const todo of todos) {
      console.log(`${todo.done ? "[x]" : "[ ]"} ${todo.id}  ${todo.title}`);
    }

    break;
  }

  case "done": {
    const id = rest[0];
    const file = join(dir, `${id}.json`);

    if (id === undefined || !existsSync(file)) {
      console.error(`there is no todo with id ${id}`);
      process.exitCode = 1;
      break;
    }

    const todo: Todo = JSON.parse(readFileSync(file, "utf8"));
    todo.done = true;
    writeFileSync(file, JSON.stringify(todo, null, 2) + "\n");

    console.log(`done ${todo.id}  ${todo.title}`);
    break;
  }

  case "remove": {
    const id = rest[0];
    const file = join(dir, `${id}.json`);

    if (id === undefined || !existsSync(file)) {
      console.error(`there is no todo with id ${id}`);
      process.exitCode = 1;
      break;
    }

    rmSync(file);

    console.log(`removed ${id}`);
    break;
  }

  default:
    console.log("usage: todo <add|list|done|remove>");
}