Handles:

• User input,
• Note creation,
• Displaying and saving the note.

Defines:

• The Note struct,
• Methods for displaying and saving,
• A constructor function New() for creating validated notes.

package main

Declares this as the main package, the entry point of the program.

import ( "bufio" "fmt" "os" "strings" "example.com/go-project/note" )

• bufio, os: for reading input from terminal.
• strings: to trim newline characters.
• fmt: for printing output.
• note: custom module for handling notes.

This function prints a prompt and reads the user's typed input.

reader := bufio.NewReader(os.Stdin) text, err := reader.ReadString('\n')

• Uses bufio.NewReader for better line reading than fmt.Scanln.
• Trims \n or \r (cross-platform newline handling).

Prompts user for both title and content:

title := getUserInput("Note Title:") content := getUserInput("Note Content:") return title, content

This is the driver logic:

title, content := getNoteData()

userNote, err := note.New(title, content)

• Calls constructor from the note package.
• Validates empty fields.

userNote.Display()

• Shows note title and content.

err = userNote.Save()

• Writes the note to a .json file.

package note

This is a custom package named note.

type Note struct { Title string `json:"title"` Content string `json:"content"` CreatedAt time.Time `json:"created_at"` }

A custom type Note with:

• Title (user-entered)
• Content (user-entered)
• CreatedAt (timestamp when note is created)

JSON tags make sure this struct is saved with the correct key names when encoded to JSON.

fmt.Printf("📝 Your note Titled %v has the following Content:\n\n%v\n", n.Title, n.Content)

• Method on Note
• Displays nicely formatted note in terminal

fileName := strings.ReplaceAll(n.Title, " ", "_") fileName = strings.ToLower(fileName) + ".json"

• Converts title like My Note to my_note.json

json, err := json.Marshal(n)

• Marshals (converts) Note struct to JSON

return os.WriteFile(fileName, json, 0644)

• Saves it to a file with read-write permission

if title == "" || content == "" { return Note{}, errors.New("invalid input") }

• Validates that both fields are not empty.

return Note{ Title: title, Content: content, CreatedAt: time.Now(), }, nil

• Returns a new note with current timestamp.

If the user enters:

Note Title: Grocery List Note Content: Buy eggs, milk, and bread. 

A file grocery_list.json is created:

{ "title": "Grocery List", "content": "Buy eggs, milk, and bread.", "created_at": "2025-07-03T15:04:05Z" }

User Input ➜ Struct Creation ➜ JSON File Write

1. We get title & content via terminal
2. Validate and construct Note struct
3. Marshal it to JSON
4. Save to file