Issue-2-DefaultWhenNotFound use default if value is undefined and key path exists. Don't use default if key exists but value is null

Author: billneff79

README.md

@@ -1,6 +1,6 @@
 # `dlv(obj, keypath)` [![NPM](https://img.shields.io/npm/v/dlv.svg)](https://npmjs.com/package/dlv) [![Build](https://travis-ci.org/developit/dlv.svg?branch=master)](https://travis-ci.org/developit/dlv)
 
-> Safely get a dot-notated path within a nested object, with ability to return a default if the full key path does not exist
+> Safely get a dot-notated path within a nested object, with ability to return a default if the full key path does not exist or the value is undefined
 
 ### Why?
 
@@ -26,7 +26,8 @@ let obj = {
 	a: {
 		b: {
 			c: 1
-			e: undefined
+			d: undefined
+			e: null
 		}
 	}
 };
@@ -40,14 +41,16 @@ delve(obj, ['a', 'b', 'c']) === 1;
 delve(obj, 'a.b') === obj.a.b;
 
 //returns undefined if the full key path does not exist and no default is specified
-delve(obj, 'a.b.c.d') === undefined;
+delve(obj, 'a.b.c.f') === undefined;
 
 //optional third parameter for default if the full key in path is missing
+delve(obj, 'a.b.c.f', 'foo') === 'foo';
+
+//or if the key exists but the value is undefined
 delve(obj, 'a.b.c.d', 'foo') === 'foo';
 
-//default is only used if full keypath does not exist.
-//Non-truthy values are still returned if they exist at the full keypath
-delve(obj, 'a.b.c.e', 'foo') === undefined;
+//Non-truthy defined values are still returned if they exist at the full keypath
+delve(obj, 'a.b.c.e', 'foo') === null;
 
 //undefined obj or key returns undefined, unless a default is supplied
 delve(undefined, 'a.b.c') === undefined;

index.js

@@ -3,5 +3,5 @@ export default function dlv(obj, key, def) {
 	if (key.split) key = key.split('.');
 	var i=0, keyLength=key.length;
 	for (; i<keyLength && obj.hasOwnProperty(key[i]); obj = obj[key[i++]]) ;
-	return i===keyLength ? obj : def;
+	return i===keyLength && typeof obj !== 'undefined' ? obj : def;
 }

test.js

@@ -5,6 +5,7 @@ var obj = {
 	undef: undefined,
 	zero: 0,
 	one: 1,
+	n: null,
 	a: {
 		two: 2,
 		b: {
@@ -20,16 +21,18 @@ var obj = {
 //optional third argument is for default when object is not found
 function check(path, value, def) {
 
-	assert.equal(delve(obj, path, def), value);
-	console.log(' ✓ delve(obj, "'+path+'")');
+	assert.strictEqual(delve(obj, path, def), value);
+	console.log(' ✓ delve(obj, "'+path+'"'+ (def ? ', "'+def+'"' : '') + ')');
 
 	if(path) {
 		var arr = path.split('.');
-		assert.equal(delve(obj, arr, def), value);
+		assert.strictEqual(delve(obj, arr, def), value);
+		console.log(' ✓ delve(obj, ' + JSON.stringify(arr) + (def ? ', "'+def+'"' : '') + ')');
 		console.log(' ✓ delve(obj, '+JSON.stringify(arr)+')');
 	}
 }
 
+console.log("> No Defaults");
 check('', undefined);
 check('one', obj.one);
 check('one.two', undefined);
@@ -41,8 +44,10 @@ check('a.b.c', obj.a.b.c);
 check('a.b.c.four', obj.a.b.c.four);
 
 //test defaults
+console.log("\n> With Defaults");
 check('', 'foo', 'foo');
-check('undef', undefined, 'foo');
+check('undef', 'foo', 'foo');
+check('n', null, 'foo');
 check('zero', 0, 'foo');
 check('a.badkey', 'foo', 'foo');
 check('a.badkey.anotherbadkey', 'foo', 'foo');