From c6bca4e1d48cdabe1906ba57e0c073653ba93246 Mon Sep 17 00:00:00 2001
From: Nick Olszanski <nick@dinosaurs-with-jetpacks.club>
Date: Tue, 3 Oct 2023 15:03:02 +0200
Subject: [PATCH] chore: clenaup code and rever tests

---
 src/lib/web-worker/worker-exec.ts | 39 ++++++++++++++-----------------
 tests/unit/worker-exec.spec.ts    | 21 ++++++++---------
 2 files changed, 27 insertions(+), 33 deletions(-)

diff --git a/src/lib/web-worker/worker-exec.ts b/src/lib/web-worker/worker-exec.ts
index 685ab84d..ee4640d6 100644
--- a/src/lib/web-worker/worker-exec.ts
+++ b/src/lib/web-worker/worker-exec.ts
@@ -118,35 +118,30 @@ export const runScriptContent = (
 
 /**
  * Replace some `this` symbols with a new value.
- * Still not perfect, but might be better than a more naive regex.
+ * Still not perfect, but might be better than a less advanced regex
  * Check out the tests for examples: tests/unit/worker-exec.spec.ts
+ *
+ * This still fails with simple strings like:
+ * 'sadly we fail at this simple string'
+ *
+ * One way to do that would be to remove all comments from code and do single / double quote counting
+ * per symbol. But this will still fail with evals.
  */
 export const replaceThisInSource = (scriptContent: string, newThis: string): string => {
-  // Best for now but not perfect
-  // Use a more complex regex to match potential preceding character and adjust replacement accordingly
-  const r0 = /(?<!([a-zA-Z0-9_$\.\'\"\`]))(\.\.\.)?this(?![a-zA-Z0-9_$:])/g;
-  const r2 = /([a-zA-Z0-9_$\.\'\"\`])?(\.\.\.)?this(?![a-zA-Z0-9_$:])/g;
-
-  return scriptContent.replace(r2, (match, p1, p2) => {
-    // console.log('\n');
-    // console.log('input: ' + scriptContent);
-    // console.log('match: ', match);
-    // console.log('p1: ', p1);
-    // console.log('p2: ', p2);
-    // console.log('\n');
+  /**
+   * Best for now but not perfect
+   * We don't use Regex lookbehind, because of Safari
+   */
+  const FIND_THIS = /([a-zA-Z0-9_$\.\'\"\`])?(\.\.\.)?this(?![a-zA-Z0-9_$:])/g;
+
+  return scriptContent.replace(FIND_THIS, (match, p1, p2) => {
+    const prefix = (p1 || '') + (p2 || '');
     if (p1 != null) {
-      return (p1 || '') + (p2 || '') + 'this';
+      return prefix + 'this';
     }
     // If there was a preceding character, include it unchanged
-    // console.log('===', scriptContent, '----', p1, p2);
-    return (p1 || '') + (p2 || '') + newThis;
+    return prefix + newThis;
   });
-
-  // 3.5
-  // const r = /(^|[^a-zA-Z0-9_$.\'\"`])\.\.\.?this(?![a-zA-Z0-9_$:])/g;
-  // return scriptContent.replace(r, '$1' + newThis);
-  // const r = /(?<!([a-zA-Z0-9_$\.\'\"\`]))(\.\.\.)?this(?![a-zA-Z0-9_$:])/g;
-  // return scriptContent.replace(r, '$2' + newThis);
 };
 
 export const run = (env: WebWorkerEnvironment, scriptContent: string, scriptUrl?: string) => {
diff --git a/tests/unit/worker-exec.spec.ts b/tests/unit/worker-exec.spec.ts
index f508f9f6..2249f964 100644
--- a/tests/unit/worker-exec.spec.ts
+++ b/tests/unit/worker-exec.spec.ts
@@ -99,7 +99,6 @@ test('We should replace `this` keyword more or less sane', ({ env, win }) => {
   };
 
   // Should replace:
-  // assert.is(r('`sadly we fail at this simple string`'), '`sadly we fail at this simple string`');
   assert.is(r('{this:123}'), '{this:123}');
   assert.is(r('a.this'), 'a.this');
   assert.is(r('[`kathis`]'), '[`kathis`]');
@@ -124,7 +123,7 @@ test('We should replace `this` keyword more or less sane', ({ env, win }) => {
     a.b.this
     let _this, This, $this
   `;
-  // const rez = replaceThisInSource(input, `__this`);
+  const rez = replaceThisInSource(input, `__this`);
 
   const out = `
     // Should replace:
@@ -145,16 +144,16 @@ test('We should replace `this` keyword more or less sane', ({ env, win }) => {
     let _this, This, $this
   `;
 
-  // assert.is(rez, out);
+  assert.is(rez, out);
 });
 
-// test('properly replaces this is js window context', ({ env, win }) => {
-//   const s = `
-//     let a = { this: 123 };
-//     window.result = a.this;
-//   `;
-//   run(env, s);
-//   assert.is(win.result, 123);
-// });
+test('properly replaces this is js window context', ({ env, win }) => {
+  const s = `
+    let a = { this: 123 };
+    window.result = a.this;
+  `;
+  run(env, s);
+  assert.is(win.result, 123);
+});
 
 test.run();