fix(iterator): fix FilterPredicate

This changes the call to a `FilterPredicate` to more closely match the type.  It cannot match exactly, because the `array` differs.

IMO, it would make more sense to provide the object with `node` and `parent` as the first parameter of a `FilterPredicate`, but that'd be a breaking change.

js/src/traversal.js

@@ -98,7 +98,7 @@ export function traverse(root, visitor) {
  * @callback FilterPredicate
  * @param {Node} node
  * @param {number} index
- * @param {Array<Node>} array
+ * @param {Array<{node: Node, parent?: Node, phase: TraversalPhase}>} array
  * @returns {boolean}
  */
 
@@ -107,10 +107,11 @@ export function traverse(root, visitor) {
  * @param {Node} root The root AST node to traverse. 
  * @param {FilterPredicate} [filter] A filter function to determine which steps to
  *      return;
- * @returns {IterableIterator<{node:Node,parent:Node|undefined,phase:TraversalPhase}>} An iterator over the AST.  
+ * @returns {IterableIterator<{node: Node, parent?: Node, phase: TraversalPhase}>} An iterator over the AST.  
  */
 export function iterator(root, filter = () => true) {
 
+    /** @type {Array<{node: Node, parent?: Node, phase: TraversalPhase}>} */
     const traversal = [];
 
     traverse(root, {
@@ -122,5 +123,5 @@ export function iterator(root, filter = () => true) {
         }
     });
 
-    return traversal.filter(filter).values();
+    return traversal.filter(({node}, index, array) => filter(node, index, array)).values();
 }

js/tests/traversal.test.js

@@ -180,6 +180,16 @@ describe("iterator()", () => {
                 ]);
             });
 
+            it("should iterate using a filter", () => {
+                const root = t.document(t.identifier("foo"));
+                const steps = [...iterator(root, node => node.type === "Document")];
+
+                expect(steps).to.deep.equal([
+                    { node: root, parent: undefined, phase: "enter" },
+                    { node: root, parent: undefined, phase: "exit" }
+                ]);
+            });
+
         });
     });
 });