add null checks and tests relative to the solved issues

index.js

@@ -33,12 +33,13 @@ function set(obj, prop, value) {
  * Get a value by a dot path.
  * @param obj The object to evaluate.
  * @param prop The path to value that should be returned.
+ * @param value The default value that should be returned when the target doesn't exist.
  */
 function get(obj, prop, value) {
 	prop = typeof prop === 'number' ? propToArray(prop.toString()) : typeof prop === 'string' ? propToArray(prop) : prop;
 
 	for (var i = 0; i < prop.length; i++) {
-		if (typeof obj !== 'object') {
+		if (obj === null || typeof obj !== 'object') {
 			return value;
 		}
 		var head = prop[i];
@@ -69,7 +70,7 @@ function _delete(obj, prop) {
 	var deletePropImmutableRec = function(obj, prop, i) {
 		var clone, head = prop[i];
 
-		if (typeof obj !== 'object' ||
+		if (obj === null || typeof obj !== 'object' ||
 			!Array.isArray(obj) && obj[head] === undefined) {
 
 			return obj;

test/dot-prop-immutable.spec.js

@@ -357,6 +357,14 @@ describe('dot-prop-immutable.spec.js', function() {
 				});
 			});
 
+			describe('when get intermediate deep prop is null', () => {
+
+				it('should return default value', () => {
+					expect(dotProp.get({b: {z: null}}, 'b.z.w')).to.equal(undefined);
+					expect(dotProp.get({b: {z: null}}, 'b.z.w', 'default')).to.equal('default');
+				});
+			});
+
 			describe('when get array[index]', () => {
 
 				it('should get index', () => {
@@ -509,6 +517,17 @@ describe('dot-prop-immutable.spec.js', function() {
 				it('invariant', objInvariant);
 			});
 
+			describe('when delete deep prop is null', () => {
+
+				before(function () {
+					result = dotProp.delete({b: {z: null}}, 'b.z.w');
+				});
+
+				it('should delete prop', () => {
+					expect(result).to.eql({b: {z: null}});
+				});
+			});
+
 			describe('when delete array[index]', () => {
 
 				before(function () {