From b9180a067df9c94aca67c20623b35d564fdca8ab Mon Sep 17 00:00:00 2001
From: j4k0xb <55899582+j4k0xb@users.noreply.github.com>
Date: Fri, 29 Dec 2023 21:22:58 +0100
Subject: [PATCH] feat: transform for loop to while loop

---
 apps/docs/src/concepts/unminify.md            | 12 ++++++++++
 .../src/unminify/test/for-to-while.test.ts    | 20 ++++++++++++++++
 .../src/unminify/transforms/for-to-while.ts   | 23 +++++++++++++++++++
 .../webcrack/src/unminify/transforms/index.ts |  1 +
 4 files changed, 56 insertions(+)
 create mode 100644 packages/webcrack/src/unminify/test/for-to-while.test.ts
 create mode 100644 packages/webcrack/src/unminify/transforms/for-to-while.ts

diff --git a/apps/docs/src/concepts/unminify.md b/apps/docs/src/concepts/unminify.md
index 2c03ef09..fb7a0b47 100644
--- a/apps/docs/src/concepts/unminify.md
+++ b/apps/docs/src/concepts/unminify.md
@@ -20,6 +20,18 @@ console["log"](a); // [!code --]
 console.log(a); // [!code ++]
 ```
 
+## for-to-while
+
+```js
+for (;;) a(); // [!code --]
+while (true) a(); // [!code ++]
+```
+
+```js
+for (; a < b;) c(); // [!code --]
+while (a < b) c(); // [!code ++]
+```
+
 ## infinity
 
 ```js
diff --git a/packages/webcrack/src/unminify/test/for-to-while.test.ts b/packages/webcrack/src/unminify/test/for-to-while.test.ts
new file mode 100644
index 00000000..56053667
--- /dev/null
+++ b/packages/webcrack/src/unminify/test/for-to-while.test.ts
@@ -0,0 +1,20 @@
+import { test } from 'vitest';
+import { testTransform } from '../../../test';
+import forToWhile from '../transforms/for-to-while';
+
+const expectJS = testTransform(forToWhile);
+
+test('empty for loop to while true', () =>
+  expectJS(`for (;;) b()`).toMatchInlineSnapshot(`while (true) b();`));
+
+test('for loop with only test to while', () =>
+  expectJS(`for (; a(); ) b();`).toMatchInlineSnapshot(`while (a()) b();`));
+
+test('ignore for loop with init or update', () =>
+  expectJS(`
+    for (let i = 0;;) {}
+    for (;; i++) {}
+  `).toMatchInlineSnapshot(`
+    for (let i = 0;;) {}
+    for (;; i++) {}
+  `));
diff --git a/packages/webcrack/src/unminify/transforms/for-to-while.ts b/packages/webcrack/src/unminify/transforms/for-to-while.ts
new file mode 100644
index 00000000..12cbcdbe
--- /dev/null
+++ b/packages/webcrack/src/unminify/transforms/for-to-while.ts
@@ -0,0 +1,23 @@
+import * as t from '@babel/types';
+import { Transform } from '../../ast-utils';
+
+export default {
+  name: 'for-to-while',
+  tags: ['safe'],
+  visitor() {
+    return {
+      ForStatement: {
+        exit(path) {
+          const { test, body, init, update } = path.node;
+          if (init || update) return;
+          path.replaceWith(
+            test
+              ? t.whileStatement(test, body)
+              : t.whileStatement(t.booleanLiteral(true), body),
+          );
+          this.changes++;
+        },
+      },
+    };
+  },
+} satisfies Transform;
diff --git a/packages/webcrack/src/unminify/transforms/index.ts b/packages/webcrack/src/unminify/transforms/index.ts
index 63eb1552..76e892eb 100644
--- a/packages/webcrack/src/unminify/transforms/index.ts
+++ b/packages/webcrack/src/unminify/transforms/index.ts
@@ -1,5 +1,6 @@
 export { default as blockStatements } from './block-statements';
 export { default as computedProperties } from './computed-properties';
+export { default as forToWhile } from './for-to-while';
 export { default as infinity } from './infinity';
 export { default as invertBooleanLogic } from './invert-boolean-logic';
 export { default as jsonParse } from './json-parse';