Test Problem: Todo App (CLI)

You have to implement a Todo app which has a command-line interface(CLI). The tests are failing right now. Write code to pass all automated tests.

Setup command

npm install

Run automated tests

npm test

Specification

The todo app has a command-line interface. For a Node.js implementation the command for running the app is node todo.js.

The todo app reads from and writes to a todo.txt text file. Each todo item occupies a single line in todo.txt. Here is an example todo.txt with 2 todo items.

water the plants
change light bulb

When a todo item is marked as completed it is removed from todo.txt and added to the done.txt text file. The line format has additional metadata separated by a single space:

x dd/mm/yyyy the text contents of the todo item

1. the x character marker
2. the current date in dd/mm/yyyy format
3. the original text

The date when the todo is marked as completed is recorded in the dd/mm/yyyy format. For example, a date like 15th August, 2020 becomes 15/08/2020.

Lookup the text files todo.txt and done.txt from where the command-line is run.

Usage

Executing the command without any arguments, or with a single argument help prints the CLI usage.

$ node todo.js help
Usage :-
$ node todo.js add "todo item"  # Add a new todo
$ node todo.js ls               # Show remaining todos
$ node todo.js del NUMBER       # Delete a todo
$ node todo.js done NUMBER      # Complete a todo
$ node todo.js help             # Show usage
$ node todo.js report           # Statistics

Show pending todos

Use the ls command. The most recently added todo is displayed first.

$ node todo.js ls
[2] change light bulb
[1] water the plants

Add a todo item

Use the add command. The text of the todo item is enclosed within double quotes.

$ node todo.js add "the thing i need to do"
Added todo: "the thing i need to do"

Delete a todo item

Use the del command to remove a todo item by its number.

$ node todo.js del 3
Deleted todo #3

Attempting to delete a non-existent todo item will display an error message.

$ node todo.js del 5
Error: todo #5 does not exist. Nothing deleted.

Mark todo item as completed

Use the done command to mark a todo item as completed by its number.

$ node todo.js done 1
Marked todo #1 as done.

Attempting to mark a non-existed todo item as completed will display an error message.

$ node todo.js done 5
Error: todo #5 does not exist.

Generate a report

Use the report command to see the latest tally of pending and completed todos.

$ node todo.js report
dd/mm/yyyy Pending : 1 Completed : 4