The DRY principle

Now, there is one more thing I want to tackle before we wrap up this section. Inside app.js we now have the same code in two places. We have the space or title body in the add command as well as in the read command:

if (command === 'add') {
  var note = notes.addNote(argv.title, argv.body);
  if (note) {
    console.log('Note created');
    console.log('--');
    console.log(`Title: ${note.title}`);
    console.log(`Body: ${note.body}`);
  } else {
    console.log('Note title taken');
  }
 } else if (command === 'list') {
   notes.getAll();
 } else if (command === 'read') {
   var note = notes.getNote(argv.title);
   if (note) {
     console.log('Note found');
     console.log('--');
     console.log(`Title: ${note.title}`);
     console.log(`Body: ${note.body}`);
   } else {
     console.log('Note not found');
 }

When you find yourself copying and pasting code, it's probably best to break that out into a function that both locations call. This is the DRY principle, which stands for Don't Repeat Yourself.