feat: #1, find node by name

package.json

@@ -38,5 +38,8 @@
     "typedoc-default-themes": "^0.5.0",
     "typedoc-plugin-external-module-name": "^1.1.1",
     "typescript": "^3.9.6"
+  },
+  "dependencies": {
+    "@newdash/newdash": "^5.10.0"
   }
 }

src/utils.ts

@@ -1,3 +1,7 @@
+import { Token, TokenType } from './lexer';
+import { forEach, isArray } from '@newdash/newdash';
+import { isPlainObject } from '@newdash/newdash/isPlainObject';
+
 export type SourceArray = number[] | Uint16Array;
 
 export function stringify(value: SourceArray, index: number, next: number): string {
@@ -31,4 +35,48 @@ export function required(value: SourceArray, index: number, comparer: Function,
   return i >= (min || 0) && i <= max ? index + i : 0;
 }
 
+export type Traverser = { [key in TokenType]?: (token: Token) => void }
+
+export function createTraverser(traverser: Traverser) {
+  return function t(node: Token | Array<any> | Object): void {
+
+    if (node instanceof Token) {
+      if (node.type in traverser) {
+        traverser[node.type](node);
+      }
+    }
+
+    if (isPlainObject(node) || isArray(node) || node instanceof Token) {
+      // @ts-ignore
+      forEach(node, (item) => {
+        t(item);
+      });
+    }
+
+
+  };
+}
+
+/**
+ * find one node by type
+ * @param node
+ * @param type
+ */
+export function findOne(node: Token, type: TokenType): Token {
+  let rt: Token;
+  createTraverser({ [type]: (v: Token) => { rt = v; } })(node);
+  return rt;
+}
+
+/**
+ * find all nodes by type
+ * @param node
+ * @param type
+ */
+export function findAll(node: Token, type: TokenType): Array<Token> {
+  const rt: Array<Token> = [];
+  createTraverser({ [type]: (v: Token) => { rt.push(v); } })(node);
+  return rt;
+}
+
 export default { stringify, is, equals, required };

test/query.spec.ts

@@ -1,4 +1,6 @@
 import { Parser } from '../src/parser';
+import { findOne } from '../src/utils';
+import { TokenType } from '../src/lexer';
 
 describe('Query Test Suite', () => {
 
@@ -58,12 +60,9 @@ describe('Query Test Suite', () => {
 
 
   it('should parse $count', () => {
-    parser.query('$count=true');
+    const ast = parser.query('$count=true');
+    const node = findOne(ast, TokenType.InlineCount);
+    expect(node).not.toBeUndefined();
   });
 
-  // it('should parser $query', () => {
-  //   parser.query('/Category/$query');
-  // });
-
-
 });