feat: free memory automatically (#5225)

lib/binding_web/test/memory.test.ts

@@ -0,0 +1,74 @@
+import { describe, expect, it } from 'vitest';
+import { gc, event, Finalizer } from './memory';
+
+// hijack finalization registry before import web-tree-sitter
+globalThis.FinalizationRegistry = Finalizer;
+
+describe('Memory Management', () => {
+  describe('call .delete()', () => {
+    it('test free memory manually', async () => {
+      const timer = setInterval(() => {
+        gc();
+      }, 100);
+      let done = 0; 
+      event.on('gc', () => {
+        done++;
+      });
+      await (async () => {
+        const { JavaScript } = await (await import('./helper')).default;
+        const  { Parser, Query } = await import('../src');
+        const parser = new Parser();
+        parser.setLanguage(JavaScript);
+        const tree = parser.parse('1+1')!;
+        const copyTree = tree.copy();
+        const cursor = tree.walk();
+        const copyCursor = cursor.copy();
+        const lookaheadIterator = JavaScript.lookaheadIterator(cursor.currentNode.nextParseState)!;
+        const query = new Query(JavaScript, '(identifier) @element');
+        parser.delete();
+        tree.delete();
+        copyTree.delete();
+        cursor.delete();
+        copyCursor.delete();
+        lookaheadIterator.delete();
+        query.delete();
+      })();
+      // wait for gc
+      await new Promise((resolve) => setTimeout(resolve, 1000));
+      clearInterval(timer);
+      // expect no gc event fired
+      expect(done).toBe(0);
+    });
+  });
+
+  describe('do not call .delete()', () => {
+    it('test free memory automatically', async () => {
+      const timer = setInterval(() => {
+        gc();
+      }, 100);
+      let done = 0;
+      const promise = new Promise((resolve) => {
+        event.on('gc', () => {
+          if (++done === 7) {
+            resolve(undefined);
+            clearInterval(timer);
+          }
+          console.log('free memory times: ', done);
+        });
+      });
+      await (async () => {
+        const { JavaScript } = await (await import('./helper')).default;
+        const  { Parser, Query } = await import('../src');
+        const parser = new Parser(); // 1
+        parser.setLanguage(JavaScript);
+        const tree = parser.parse('1+1')!; // 2
+        tree.copy(); // 3
+        const cursor = tree.walk(); // 4
+        cursor.copy(); // 5
+        JavaScript.lookaheadIterator(cursor.currentNode.nextParseState)!; // 6
+        new Query(JavaScript, '(identifier) @element'); // 7
+      })();
+      await promise;
+    });
+  });
+});