From 725f3caa55d5c0cf1ed244101b02732f85bd7fc2 Mon Sep 17 00:00:00 2001
From: Josh Baker <joshbaker77@gmail.com>
Date: Fri, 12 Aug 2016 08:39:08 -0700
Subject: [PATCH] exists function

---
 README.md     | 15 ++++++++++++---
 gjson.go      | 11 +++++++++++
 gjson_test.go |  3 +++
 3 files changed, 26 insertions(+), 3 deletions(-)

diff --git a/README.md b/README.md
index 527eddc..f9a3397 100644
--- a/README.md
+++ b/README.md
@@ -48,7 +48,10 @@ This will print:
 Prichard
 ```
 
-A path is a series of keys separated by a dot. A key may contain special wildcard characters '*' and '?'. To access an array value use the index as the key. To get the number of elements in an array use the '#' character.
+A path is a series of keys separated by a dot. 
+A key may contain special wildcard characters '\*' and '?'. 
+To access an array value use the index as the key. 
+To get the number of elements in an array use the '#' character.
 The dot and wildcard character can be escaped with '\'.
 ```
 {
@@ -69,14 +72,14 @@ The dot and wildcard character can be escaped with '\'.
 
 ## Result Type
 
-GJSON supports the json types `string`, `number`, `bool`, and `null`. Arrays and Objects are returned as their raw json types. 
+GJSON supports the json types `string`, `number`, `bool`, and `null`. 
+Arrays and Objects are returned as their raw json types. 
 
 The `Result` type holds one of these types:
 
 ```
 bool, for JSON booleans
 float64, for JSON numbers
-Number, for JSON numbers
 string, for JSON string literals
 nil, for JSON null
 ```
@@ -89,6 +92,12 @@ result.Value()  // interface{} which may be nil, string, float64, or bool
 
 // Or just get the value in one step.
 gjson.Get(json, "name.last").Value()
+
+// Check for the existence of a value.
+if gjson.Get(json, "name.last").Exists(){
+	println("value exists")
+}
+
 ```
 
 To directly access the value from its original type:
diff --git a/gjson.go b/gjson.go
index e6dad09..abc693d 100644
--- a/gjson.go
+++ b/gjson.go
@@ -51,6 +51,15 @@ func (t Result) String() string {
 	}
 }
 
+// Exists returns true if value exists.
+//
+//  if gjson.Get(json, "name.last").Exists(){
+//		println("value exists")
+//  }
+func (t Result) Exists() bool {
+	return t.Type != Null && len(t.Raw) != 0
+}
+
 // Value returns one of these types:
 //
 //	bool, for JSON booleans
@@ -97,6 +106,8 @@ type frame struct {
 // A key may contain special wildcard characters '*' and '?'.
 // To access an array value use the index as the key.
 // To get the number of elements in an array use the '#' character.
+// The dot and wildcard character can be escaped with '\'.
+//
 //  {
 //    "name": {"first": "Tom", "last": "Anderson"},
 //    "age":37,
diff --git a/gjson_test.go b/gjson_test.go
index a44cb5e..8b058f7 100644
--- a/gjson_test.go
+++ b/gjson_test.go
@@ -103,6 +103,9 @@ var basicJSON = `{"age":100, "name":{"here":"B\\\"R"},
 func TestBasic(t *testing.T) {
 	var token Result
 
+	if !Get(basicJSON, "name.last").Exists() {
+		t.Fatal("expected true, got false")
+	}
 	token = Get(basicJSON, "name.here")
 	if token.String() != "B\\\"R" {
 		t.Fatal("expecting 'B\\\"R'", "got", token.String())