From fd540a5237b1042973d2e76f988112658f57f311 Mon Sep 17 00:00:00 2001
From: Tobie Morgan Hitchcock <tobie@abcum.com>
Date: Mon, 24 Oct 2016 14:16:33 +0100
Subject: [PATCH] Enable checking for existing and non-null items

---
 util/data/data.go      |  8 ++++++++
 util/data/data_test.go | 10 ++++++++++
 2 files changed, 18 insertions(+)

diff --git a/util/data/data.go b/util/data/data.go
index 074a1403..3cd2aea3 100644
--- a/util/data/data.go
+++ b/util/data/data.go
@@ -78,6 +78,14 @@ func (d *Doc) Reset(path ...string) (*Doc, error) {
 	return d.Set(nil, path...)
 }
 
+// Valid checks whether the value at the specified path is nil.
+func (d *Doc) Valid(path ...string) bool {
+	if !d.Exists(path...) {
+		return false
+	}
+	return d.Get(path...).Data() != nil
+}
+
 // Array sets the specified path to an array.
 func (d *Doc) Array(path ...string) (*Doc, error) {
 	return d.Set([]interface{}{}, path...)
diff --git a/util/data/data_test.go b/util/data/data_test.go
index 70075ee0..6937b3f0 100644
--- a/util/data/data_test.go
+++ b/util/data/data_test.go
@@ -334,6 +334,16 @@ func TestOperations(t *testing.T) {
 
 	// ----------------------------------------------------------------------------------------------------
 
+	Convey("Is unset item valid", t, func() {
+		So(doc.Valid("the.none"), ShouldBeFalse)
+	})
+
+	Convey("Is item valid", t, func() {
+		So(doc.Valid("the.item"), ShouldBeTrue)
+	})
+
+	// ----------------------------------------------------------------------------------------------------
+
 	Convey("Can get object keys and vals", t, func() {
 		So(doc.Keys("the.item.object").Data(), ShouldResemble, []interface{}{"enabled"})
 		So(doc.Vals("the.item.object").Data(), ShouldResemble, []interface{}{false})