From 8e8823353cb4ca9e9f3ead11705b9358e83a8c07 Mon Sep 17 00:00:00 2001
From: aeneasr <aeneas@ory.sh>
Date: Mon, 13 Jan 2020 11:51:52 +0100
Subject: [PATCH] Add @this modifier

This modifier returns the current element as-is and can be used
to retrieve the JSON document itself. It is equivalent to the `#/` JSON Pointer.

Closes #149
---
 SYNTAX.md     | 1 +
 gjson.go      | 8 +++++++-
 gjson_test.go | 6 ++++++
 3 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/SYNTAX.md b/SYNTAX.md
index a57a4d6..ed584de 100644
--- a/SYNTAX.md
+++ b/SYNTAX.md
@@ -186,6 +186,7 @@ There are currently three built-in modifiers:
 - `@reverse`: Reverse an array or the members of an object.
 - `@ugly`: Remove all whitespace from JSON.
 - `@pretty`: Make the JSON more human readable.
+- `@this`: Returns the current element. Can be used to retrieve the root element.
 
 #### Modifier arguments
 
diff --git a/gjson.go b/gjson.go
index 8705ee2..203db3d 100644
--- a/gjson.go
+++ b/gjson.go
@@ -1989,7 +1989,7 @@ func runeit(json string) rune {
 }
 
 // unescape unescapes a string
-func unescape(json string) string { //, error) {
+func unescape(json string) string { // , error) {
 	var str = make([]byte, 0, len(json))
 	for i := 0; i < len(json); i++ {
 		switch {
@@ -2746,6 +2746,7 @@ var modifiers = map[string]func(json, arg string) string{
 	"pretty":  modPretty,
 	"ugly":    modUgly,
 	"reverse": modReverse,
+	"this":    modThis,
 }
 
 // AddModifier binds a custom modifier command to the GJSON syntax.
@@ -2783,6 +2784,11 @@ func modPretty(json, arg string) string {
 	return bytesString(pretty.Pretty(stringBytes(json)))
 }
 
+// @this returns the current element. Can be used to retrieve the root element.
+func modThis(json, arg string) string {
+	return json
+}
+
 // @ugly modifier removes all whitespace.
 func modUgly(json, arg string) string {
 	return bytesString(pretty.Ugly(stringBytes(json)))
diff --git a/gjson_test.go b/gjson_test.go
index 5f2711d..04031ec 100644
--- a/gjson_test.go
+++ b/gjson_test.go
@@ -1519,6 +1519,12 @@ func TestModifier(t *testing.T) {
 	if res != json {
 		t.Fatalf("expected '%v', got '%v'", json, res)
 	}
+	if res := Get(res, "@this").String(); res != json {
+		t.Fatalf("expected '%v', got '%v'", json, res)
+	}
+	if res := Get(res, "other.@this").String(); res != `{"hello":"world"}` {
+		t.Fatalf("expected '%v', got '%v'", json, res)
+	}
 	res = Get(res, "@pretty|@reverse|arr|@reverse|2").String()
 	if res != "4" {
 		t.Fatalf("expected '%v', got '%v'", "4", res)