No JSON in sight

Why does json.Marshal produce empty structs in the JSON text output?

type Person struct {	name string	age int } p := Person{"Alice", 22} jsonData, _ := json.Marshal(p) fmt.Println(string(jsonData))

{} 

Answer

Only exported fields of a Go struct will be present in the JSON output.

type Person struct { Name string // Changed to capital N Age int // Changed to capital A } p := Person{"Alice", 22} jsonData, _ := json.Marshal(p) fmt.Println(string(jsonData))

{"Name":"Alice","Age":22} 

You can specify the JSON field name explicitly with a json: tag.

type Person struct {	Name string `json:"name"`	Age int `json:"age"` } p := Person{"Alice", 22} jsonData, _ := json.Marshal(p) fmt.Println(string(jsonData))

{"name":"Alice","age":22} 

See JSON by example for an extensive guide to the Go JSON library.

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