Supplying nonparseable nb argument now throws.

README.md

@@ -302,11 +302,16 @@ var newList = cursor.select('one').shift('two');
 Splices the selected list. This will of course fail if the selected node is not a list.
 
 The `splice` specifications works the same as for [`Array.prototype.splice`](https://developer.mozilla.org/fr/docs/Web/JavaScript/Reference/Objets_globaux/Array/splice).
+There is one exception though: Per specification, splice deletes no values if the `deleteCount` argument is not parseable as a number.
+The `splice` implementation of Baobab instead throws an error, if the given `deleteCount` argument could not be parsed.
 
 ```js
 // Splicing the list
 var newList = cursor.splice([1, 1]);
 
+// Omitting the deleteCount argument makes splice delete no elements. 
+var newList = cursor.splice([1]);
+
 // Inserting an item etc.
 var newList = cursor.splice([1, 0, 'newItem']);
 var newList = cursor.splice([1, 0, 'newItem1', 'newItem2']);

src/helpers.js

@@ -570,12 +570,12 @@ export function solveUpdate(affectedPaths, comparedPaths) {
  * @return {array}                 - The spliced array.
  */
 export function splice(array, startIndex, nb, ...elements) {
-  if (nb === undefined) {
+  if (nb === undefined)
     nb = array.length - startIndex;
-  }
-  else if (nb === null || Number.isNaN(Number.parseInt(nb))) {
+  else if (nb === null)
     nb = 0;
-  }
+  else if (Number.isNaN(Number.parseInt(nb)))
+    throw new Error(`argument nb ${nb} can not be parsed into a number!`);
   nb = Math.max(0, nb);
 
   // Solving startIndex

src/type.js

@@ -114,6 +114,8 @@ type.primitive = function(target) {
 type.splicer = function(target) {
   if (!type.array(target) || target.length < 1)
     return false;
+  if(target.length > 1 && Number.isNaN(Number.parseInt(target[1])))
+    return false;
 
   return anyOf(target[0], ['number', 'function', 'object']);
 };

test/suites/helpers.js

@@ -225,7 +225,7 @@ describe('Helpers', function() {
     });
 
     describe('Issue #472 - tree/cursor.splice does not conform with the specification as of ES6 (ECMAScript 2015)', function () {
-      it('should be possible to splice an array when omitting the nb (deleteCount) argument', function () {
+      it('should be possible to splice an array when omitting the nb (deleteCount) argument or passing null', function () {
         const array = [0, 1, 2, 3, 4];
 
         assert.deepEqual(splice(array, 2), [0, 1]);
@@ -235,12 +235,16 @@ describe('Helpers', function() {
         assert.deepEqual(splice(array, 2, null), [0, 1, 2, 3, 4]);
       });
 
-      it('should delete no values when supplying an argument which is not parseable as number', function () {
+      it('should throw an error when supplying an argument for nb (deleteCount) which is not parseable as number', function () {
         const array = [0, 1, 2, 3, 4];
 
-        assert.deepEqual(splice(array, 2, "a"), [0, 1, 2, 3, 4]);
+        assert.throws(function () {
+			splice(array, 2, "a");
+		}, Error);
 
-        assert.deepEqual(splice(array, 2, {}), [0, 1, 2, 3, 4]);
+        assert.throws(function () {
+			splice(array, 2, {});
+		}, Error);
       });
     });
   });