Challenge 3 — Solution

Task: Write a function fetchUser(id int) (User, error) that fetches
from https://jsonplaceholder.typicode.com/users/{id}, unmarshals
into a User struct with at least Name and Email fields (with json
tags), properly closing the response body with defer. Call it and
print the result, handling any error.

package main

import (
	"encoding/json"
	"fmt"
	"io"
	"net/http"
)

type User struct {
	Name  string `json:"name"`
	Email string `json:"email"`
}

func fetchUser(id int) (User, error) {
	var user User

	resp, err := http.Get(fmt.Sprintf("https://jsonplaceholder.typicode.com/users/%d", id))
	if err != nil {
		return user, err
	}
	defer resp.Body.Close()

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return user, err
	}

	err = json.Unmarshal(body, &user)
	return user, err
}

func main() {
	user, err := fetchUser(1)
	if err != nil {
		fmt.Println("Error:", err)
		return
	}

	fmt.Println(user.Name)
	fmt.Println(user.Email)
}


Expected output:

Leanne Graham
Sincere@april.biz

Notes:
- defer resp.Body.Close() is placed immediately after confirming
  err is nil from http.Get — this guarantees the body gets closed
  once fetchUser returns, regardless of whether the later ReadAll or
  Unmarshal steps succeed or fail.
- fetchUser returns the (possibly still-empty) user struct alongside
  any error at each early-return point, matching the same
  multi-return-value pattern from Fundamentals Chapter 5.
- The User struct only defines Name and Email — the real API
  response includes many more fields (address, phone, etc.), but
  json.Unmarshal simply ignores any JSON fields that don't have a
  matching struct field.