How to Read JSON Files as JSON Objects in Go?

Reading JSON Files as JSON Objects in Go

To read a JSON file as a JSON object in Go, it's crucial to understand the concept of pointers and type assertion.

Reading the JSON File

plan, err := ioutil.ReadFile(filename)
if err != nil {
    log.Fatal(err)
}

Unmarshaling the Data

To store the JSON object, you'll need a pointer to a variable, as specified in the Go documentation:

var data interface{}
if err := json.Unmarshal(plan, &data); err != nil {
    log.Fatal(err)
}

This stores the JSON object in the memory location pointed to by data.

Accessing the JSON Object

Since data is an interface, you must use type assertion to access its underlying values:

switch data := data.(type) {
case map[string]interface{}:
    // Loop through the map as a JSON object
    for key, value := range data {
        fmt.Println(key, value)
    }
case []interface{}:
    // Loop through the slice as a JSON array
    for _, value := range data {
        fmt.Println(value)
    }
default:
    // Handle other types as needed
}

Marshaling for Debugging

If you need to view the JSON object as a string for debugging purposes, you can use:

jsonString, err := json.Marshal(data)
if err != nil {
    log.Fatal(err)
}
fmt.Println(string(jsonString))

Note:

• Ensure that the JSON file is correctly formatted and contains valid JSON data.
• Use a specific data structure to populate your JSON when possible, rather than an empty interface.

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