tidwall/sjson

$ go get -u github.com/tidwall/sjson

package main

import "github.com/tidwall/sjson"

const json = `{"name":{"first":"Janet","last":"Prichard"},"age":47}`

func main() {
	value, _ := sjson.Set(json, "name.last", "Anderson")
	println(value)
}

{"name":{"first":"Janet","last":"Anderson"},"age":47}

{
  "name": {"first": "Tom", "last": "Anderson"},
  "age":37,
  "children": ["Sara","Alex","Jack"],
  "fav.movie": "Deer Hunter",
  "friends": [
	{"first": "James", "last": "Murphy"},
	{"first": "Roger", "last": "Craig"}
  ]
}

"name.last"          >> "Anderson"
"age"                >> 37
"children.1"         >> "Alex"
"friends.1.last"     >> "Craig"

"children.-1"  >> appends a new value to the end of the children array

{
  "users":{
    "2313":{"name":"Sara"},
    "7839":{"name":"Andy"}
  }
}

"users.:2313.name"    >> "Sara"

sjson.Set(`{"key":true}`, "key", nil)
sjson.Set(`{"key":true}`, "key", false)
sjson.Set(`{"key":true}`, "key", 1)
sjson.Set(`{"key":true}`, "key", 10.5)
sjson.Set(`{"key":true}`, "key", "hello")
sjson.Set(`{"key":true}`, "key", []string{"hello", "world"})
sjson.Set(`{"key":true}`, "key", map[string]interface{}{"hello":"world"})

value, _ := sjson.Set("", "name", "Tom")
println(value)

// Output:
// {"name":"Tom"}

value, _ := sjson.Set("", "name.last", "Anderson")
println(value)

// Output:
// {"name":{"last":"Anderson"}}

value, _ := sjson.Set(`{"name":{"last":"Anderson"}}`, "name.first", "Sara")
println(value)

// Output:
// {"name":{"first":"Sara","last":"Anderson"}}

value, _ := sjson.Set(`{"name":{"last":"Anderson"}}`, "name.last", "Smith")
println(value)

// Output:
// {"name":{"last":"Smith"}}

value, _ := sjson.Set(`{"friends":["Andy","Carol"]}`, "friends.2", "Sara")
println(value)

// Output:
// {"friends":["Andy","Carol","Sara"]

value, _ := sjson.Set(`{"friends":["Andy","Carol"]}`, "friends.-1", "Sara")
println(value)

// Output:
// {"friends":["Andy","Carol","Sara"]

value, _ := sjson.Set(`{"friends":["Andy","Carol"]}`, "friends.4", "Sara")
println(value)

// Output:
// {"friends":["Andy","Carol",null,null,"Sara"]

value, _ := sjson.Delete(`{"name":{"first":"Sara","last":"Anderson"}}`, "name.first")
println(value)

// Output:
// {"name":{"last":"Anderson"}}

value, _ := sjson.Delete(`{"friends":["Andy","Carol"]}`, "friends.1")
println(value)

// Output:
// {"friends":["Andy"]}

value, _ := sjson.Delete(`{"friends":["Andy","Carol"]}`, "friends.-1")
println(value)

// Output:
// {"friends":["Andy"]}

Benchmark_SJSON-8                  	 3000000	       805 ns/op	    1077 B/op	       3 allocs/op
Benchmark_SJSON_ReplaceInPlace-8   	 3000000	       449 ns/op	       0 B/op	       0 allocs/op
Benchmark_JSON_Map-8               	  300000	     21236 ns/op	    6392 B/op	     150 allocs/op
Benchmark_JSON_Struct-8            	  300000	     14691 ns/op	    1789 B/op	      24 allocs/op
Benchmark_Gabs-8                   	  300000	     21311 ns/op	    6752 B/op	     150 allocs/op
Benchmark_FFJSON-8                 	  300000	     17673 ns/op	    3589 B/op	      47 allocs/op
Benchmark_EasyJSON-8               	 1500000	      3119 ns/op	    1061 B/op	      13 allocs/op

{
  "widget": {
    "debug": "on",
    "window": {
      "title": "Sample Konfabulator Widget",
      "name": "main_window",
      "width": 500,
      "height": 500
    },
    "image": { 
      "src": "Images/Sun.png",
      "hOffset": 250,
      "vOffset": 250,
      "alignment": "center"
    },
    "text": {
      "data": "Click Here",
      "size": 36,
      "style": "bold",
      "vOffset": 100,
      "alignment": "center",
      "onMouseUp": "sun1.opacity = (sun1.opacity / 100) * 90;"
    }
  }
}    

widget.window.name
widget.image.hOffset
widget.text.onMouseUp