From 62892351c5f689619811f111e764b051a401ef2b Mon Sep 17 00:00:00 2001
From: Josh Baker <joshbaker77@gmail.com>
Date: Wed, 30 Nov 2016 10:50:59 -0700
Subject: [PATCH] added ForEach function

---
 README.md     | 14 ++++++++++++
 gjson.go      | 60 +++++++++++++++++++++++++++++++++++++++++++++++++++
 gjson_test.go | 37 +++++++++++++++++++++++++++++++
 3 files changed, 111 insertions(+)

diff --git a/README.md b/README.md
index 276b05d..786afbe 100644
--- a/README.md
+++ b/README.md
@@ -185,6 +185,20 @@ name := gjson.Get(json, `programmers.#[lastName="Hunter"].firstName`)
 println(name.String())  // prints "Elliotte"
 ```
 
+## Iterate through an object or array
+
+The `ForEach` function allows for quickly iterating through an object or array. 
+The key and value are passed to the iterator function for objects.
+Only the value is passed for arrays.
+Returning `false` from an iterator will stop iteration.
+
+```go
+result := gjson.Get(json, "programmers")
+result.ForEach(func(key, value Result) bool{
+	println(value.String()) 
+	return true // keep iterating
+})
+```
 
 ## Simple Parse and Get
 
diff --git a/gjson.go b/gjson.go
index 1f077fa..cd8dae6 100644
--- a/gjson.go
+++ b/gjson.go
@@ -152,6 +152,66 @@ func (t Result) Array() []Result {
 	return r.a
 }
 
+// ForEach iterates through values.
+// If the result represents a non-existent value, then no values will be iterated.
+// If the result is an Object, the iterator will pass the key and value of each item.
+// If the result is an Array, the iterator will only pass the value of each item.
+// If the result is not a JSON array or object, the iterator will pass back one value equal to the result.
+func (t Result) ForEach(iterator func(key, value Result) bool) {
+	if !t.Exists() {
+		return
+	}
+	if t.Type != JSON {
+		iterator(Result{}, t)
+		return
+	}
+	json := t.Raw
+	var keys bool
+	var i int
+	var key, value Result
+	for ; i < len(json); i++ {
+		if json[i] == '{' {
+			i++
+			key.Type = String
+			keys = true
+			break
+		} else if json[i] == '[' {
+			i++
+			break
+		}
+		if json[i] > ' ' {
+			return
+		}
+	}
+	var str string
+	var vesc bool
+	var ok bool
+	for ; i < len(json); i++ {
+		if keys {
+			if json[i] != '"' {
+				continue
+			}
+			i, str, vesc, ok = parseString(json, i+1)
+			if !ok {
+				return
+			}
+			if vesc {
+				key.Str = unescape(str[1 : len(str)-1])
+			} else {
+				key.Str = str[1 : len(str)-1]
+			}
+			key.Raw = str
+		}
+		i, value, ok = parseAny(json, i, true)
+		if !ok {
+			return
+		}
+		if !iterator(key, value) {
+			return
+		}
+	}
+}
+
 // Map returns back an map of values. The result should be a JSON array.
 func (t Result) Map() map[string]Result {
 	if t.Type != JSON {
diff --git a/gjson_test.go b/gjson_test.go
index 466dd2e..be61517 100644
--- a/gjson_test.go
+++ b/gjson_test.go
@@ -163,6 +163,43 @@ func TestBasic(t *testing.T) {
 	if mtok.String() != `["Brett","Elliotte"]` {
 		t.Fatalf("expected %v, got %v", `["Brett","Elliotte"]`, mtok.String())
 	}
+
+	mtok = get(basicJSON, `loggy.programmers`)
+	var count int
+	mtok.ForEach(func(key, value Result) bool {
+		if key.Exists() {
+			t.Fatalf("expected %v, got %v", false, key.Exists())
+		}
+		count++
+		if count == 3 {
+			return false
+		}
+		if count == 1 {
+			i := 0
+			value.ForEach(func(key, value Result) bool {
+				switch i {
+				case 0:
+					if key.String() != "firstName" || value.String() != "Brett" {
+						t.Fatalf("expected %v/%v got %v/%v", "firstName", "Brett", key.String(), value.String())
+					}
+				case 1:
+					if key.String() != "lastName" || value.String() != "McLaughlin" {
+						t.Fatalf("expected %v/%v got %v/%v", "lastName", "McLaughlin", key.String(), value.String())
+					}
+				case 2:
+					if key.String() != "email" || value.String() != "aaaa" {
+						t.Fatalf("expected %v/%v got %v/%v", "email", "aaaa", key.String(), value.String())
+					}
+				}
+				i++
+				return true
+			})
+		}
+		return true
+	})
+	if count != 3 {
+		t.Fatalf("expected %v, got %v", 3, count)
+	}
 	mtok = get(basicJSON, `loggy.programmers.#[age=101].firstName`)
 	if mtok.String() != "1002.3" {
 		t.Fatalf("expected %v, got %v", "1002.3", mtok.String())