Is there a jq wrapper for golang that can produce human readable JSON output?

Question

I\'m writing a go program (let\'s call it foo) that outputs JSON on the Standard Out.

$ ./foo
{\"id\":\"uuid1\",\"name\":\"John Smith\"}{\"id\":\"uuid2\",\"         


        

Answer 1

The encoding/json package supports pretty output out-of-the-box. You may use json.MarshalIndent(). Or if you're using json.Encoder, then call its Encoder.SetIndent() (new since Go 1.7) method prior to calling Encoder.Encode().

Examples:

m := map[string]interface{}{"id": "uuid1", "name": "John Smith"}

data, err := json.MarshalIndent(m, "", "  ")
if err != nil {
    panic(err)
}
fmt.Println(string(data))

enc := json.NewEncoder(os.Stdout)
enc.SetIndent("", "  ")
if err := enc.Encode(m); err != nil {
    panic(err)
}

Output (try it on the Go Playground):

{
  "id": "uuid1",
  "name": "John Smith"
}
{
  "id": "uuid1",
  "name": "John Smith"
}

If you just want to format a "ready" JSON text, you may use the json.Indent() function:

src := `{"id":"uuid1","name":"John Smith"}`

dst := &bytes.Buffer{}
if err := json.Indent(dst, []byte(src), "", "  "); err != nil {
    panic(err)
}
fmt.Println(dst.String())

Output (try it on the Go Playground):

{
  "id": "uuid1",
  "name": "John Smith"
}

The 2 string parameters to these indent functions are:

prefix, indent string

Explanation is in the docs:

Each element in a JSON object or array begins on a new, indented line beginning with prefix followed by one or more copies of indent according to the indentation nesting.

So each newline will be started with prefix, which will be followed by 0 or more copies of indent, depending on the nesting level.

It becomes clear and obvious if you specify values for them like this:

json.Indent(dst, []byte(src), "+", "-")

Testing it with embedded objects:

src := `{"id":"uuid1","name":"John Smith","embedded:":{"fieldx":"y"}}`

dst := &bytes.Buffer{}
if err := json.Indent(dst, []byte(src), "+", "-"); err != nil {
    panic(err)
}
fmt.Println(dst.String())

Output (try it on the Go Playground):

{
+-"id": "uuid1",
+-"name": "John Smith",
+-"embedded:": {
+--"fieldx": "y"
+-}
+}