[Fix] continue iterating properly when items are removed

Fixes #18

index.js

@@ -132,6 +132,7 @@ function walk(root, cb) {
 			parent: parents[parents.length - 1],
 			parents: parents,
 			key: path[path.length - 1],
+			removedKeys: { __proto__: null },
 			isRoot: path.length === 0,
 			level: path.length,
 			circular: null,
@@ -144,15 +145,17 @@ function walk(root, cb) {
 			},
 			delete: function (stopHere) {
 				delete state.parent.node[state.key];
+				state.parent.removedKeys[state.key] = true;
 				if (stopHere) { keepGoing = false; }
 			},
 			remove: function (stopHere) {
 				if (isArray(state.parent.node)) {
 					state.parent.node.splice(state.key, 1);
+					state.parent.removedKeys[state.key] = true;
+					if (stopHere) { keepGoing = false; }
 				} else {
-					delete state.parent.node[state.key];
+					state.delete(stopHere);
 				}
-				if (stopHere) { keepGoing = false; }
 			},
 			keys: null,
 			before: function (f) { modifiers.before = f; },
@@ -208,6 +211,11 @@ function walk(root, cb) {
 			updateState();
 
 			forEach(state.keys, function (key, i) {
+				var prevIsRemoved = (i - 1) in state.removedKeys;
+				if (prevIsRemoved) {
+					key = state.keys[i - 1]; // eslint-disable-line no-param-reassign
+				}
+
 				path[path.length] = (key);
 
 				if (modifiers.pre) { modifiers.pre.call(state, state.node[key], key); }
@@ -217,6 +225,7 @@ function walk(root, cb) {
 					immutable
 					&& hasOwnProperty.call(state.node, key)
 					&& !isWritable(state.node, key)
+					&& !prevIsRemoved
 				) {
 					state.node[key] = child.node;
 				}

test/mutability.js

@@ -290,3 +290,30 @@ test('stringToObject', function (t) {
 	t.deepEqual(obj, { a: 1, b: 20, c: [3, 40] });
 	t.end();
 });
+
+test('array item removal', function (t) {
+	var obj = [
+		function a() {},
+		function b() {},
+		'a',
+	];
+
+	function cb(x) {
+		if (x !== obj) {
+			// console.log("**", x, typeof x)
+			if (typeof x === 'function') { this.remove(); }
+		}
+	}
+
+	var result = traverse(obj, { immutable: true }).forEach(cb);
+
+	t.equal(obj.length, 3, 'immutable: makes no changes');
+
+	t.deepEqual(result, ['a'], 'immutable result: removes all functions');
+
+	traverse(obj).forEach(cb);
+
+	t.deepEqual(obj, ['a'], 'removes all functions');
+
+	t.end();
+});