05 The add command

Goal: wire up the add command in cli.js so node cli.js add "buy milk" persists the todo and confirms it.

Reading command-line arguments

process.argv is an array of strings. The first two entries are the node binary and the script path; everything after that is user input.

// args.js
const [cmd, ...rest] = process.argv.slice(2);
console.log(cmd);    // first argument
console.log(rest);   // remaining arguments as an array

node args.js add "buy milk"
# add
# [ 'buy milk' ]

The add command

Create cli.js:

// cli.js
const { readTodos, writeTodos, addTodo, formatList } = require("./todo");

const FILE = process.env.TODO_FILE || "todos.json";
const [cmd, ...rest] = process.argv.slice(2);

if (cmd === "add") {
  const text = rest.join(" ");
  if (!text) {
    console.error('usage: node cli.js add "text"');
    process.exit(1);
  }
  writeTodos(FILE, addTodo(readTodos(FILE), text));
  console.log(`Added: ${text}`);
}

Checkpoint

node cli.js add "buy milk"
# Added: buy milk

Check todos.json — it should contain:

[
  {
    "text": "buy milk",
    "done": false
  }
]

Run again to add a second todo:

node cli.js add "walk dog"
# Added: walk dog

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Next: 06 The list command