The `encoding/json` package

encoding/json Package

The encoding/json package provides functions for encoding and decoding JSON data. It is part of the standard library in Go.

---

1. json.Marshal

Converts a Go object into a JSON byte slice.

package main

import (
  "encoding/json"
  "fmt"
)

func main() {
  data := map[string]interface{}{
    "name": "Areen",
    "age":  16,
  }
  jsonData, err := json.Marshal(data)
  if err != nil {
    fmt.Println("Error:", err)
    return
  }
  fmt.Println(string(jsonData))
}

Output:

{"name":"Areen","age":16}

---

2. json.MarshalIndent

Converts a Go object into a JSON byte slice with indentation.

package main

import (
  "encoding/json"
  "fmt"
)

func main() {
  data := map[string]interface{}{
    "name": "Areen",
    "age":  16,
  }
  jsonData, err := json.MarshalIndent(data, "", "  ")
  if err != nil {
    fmt.Println("Error:", err)
    return
  }
  fmt.Println(string(jsonData))
}

Output:

{
  "name": "Areen",
  "age": 16
}

---

3. json.Unmarshal

Parses JSON data into a Go object.

package main

import (
  "encoding/json"
  "fmt"
)

func main() {
  jsonData := `{"name":"Areen","age":16}`
  var data map[string]interface{}
  err := json.Unmarshal([]byte(jsonData), &data)
  if err != nil {
    fmt.Println("Error:", err)
    return
  }
  fmt.Println(data)
}

Output:

map[age:16 name:Areen]

---

4. json.NewDecoder and Decoder.Decode

Reads JSON data from an io.Reader.

package main

import (
  "encoding/json"
  "fmt"
  "strings"
)

func main() {
  jsonData := `{"name":"Areen","age":16}`
  reader := strings.NewReader(jsonData)
  decoder := json.NewDecoder(reader)
  var data map[string]interface{}
  err := decoder.Decode(&data)
  if err != nil {
    fmt.Println("Error:", err)
    return
  }
  fmt.Println(data)
}

Output:

map[age:16 name:Areen]

---

5. json.NewEncoder and Encoder.Encode

Writes a Go object as JSON to an io.Writer.

package main

import (
  "encoding/json"
  "os"
)

func main() {
  data := map[string]interface{}{
    "name": "Areen",
    "age":  16,
  }
  encoder := json.NewEncoder(os.Stdout)
  err := encoder.Encode(data)
  if err != nil {
    fmt.Println("Error:", err)
  }
}

Output:

{"name":"Areen","age":16}

---

6. json.Valid

Checks if a byte slice contains valid JSON.

package main

import (
  "encoding/json"
  "fmt"
)

func main() {
  jsonData := `{"name":"Areen","age":16}`
  if json.Valid([]byte(jsonData)) {
    fmt.Println("Valid JSON")
  } else {
    fmt.Println("Invalid JSON")
  }
}

Output:

Valid JSON

---

7. json.RawMessage

Allows delaying or customizing JSON decoding.

package main

import (
  "encoding/json"
  "fmt"
)

func main() {
  jsonData := `{"name":"Areen","details":{"age":16}}`
  var data map[string]json.RawMessage
  err := json.Unmarshal([]byte(jsonData), &data)
  if err != nil {
    fmt.Println("Error:", err)
    return
  }
  fmt.Println(string(data["details"]))
}

Output:

{"age":16}

---

These examples demonstrate how to use the encoding/json package effectively. Let me know if you’d like further explanations or additional use cases!