fix: default parameters with gap (#69)

j4k0xb · Mar 22, 2024 · 98ca4a9 · 98ca4a9
1 parent d37d27d
commit 98ca4a9
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diff --git a/packages/webcrack/src/transpile/test/default-parameters.test.ts b/packages/webcrack/src/transpile/test/default-parameters.test.ts
@@ -25,6 +25,16 @@ describe('Babel', () => {
       function f(x = 1, y) {}
     `));
 
+  test('default parameter with gap before the last one', () =>
+    expectJS(`
+      function f(e) {
+        var x = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : {};
+        var y = arguments.length > 5 ? arguments[5] : undefined;
+      }
+    `).toMatchInlineSnapshot(`
+      function f(e, x = {}, _param, _param2, _param3, y) {}
+    `));
+
   test('default parameter (loose)', () =>
     expectJS(`
       function f(x, y) {

diff --git a/packages/webcrack/src/transpile/transforms/default-parameters.ts b/packages/webcrack/src/transpile/transforms/default-parameters.ts
@@ -82,13 +82,19 @@ export default {
           if (!t.isFunction(fn) || path.key !== 0) return;
 
           if (defaultParam.match(path.node)) {
+            for (let i = fn.params.length; i < index.current!.value; i++) {
+              fn.params[i] = t.identifier(path.scope.generateUid('param'));
+            }
             fn.params[index.current!.value] = t.assignmentPattern(
               varName.current!,
               defaultExpression.current!,
             );
             path.remove();
             this.changes++;
           } else if (normalParam.match(path.node)) {
+            for (let i = fn.params.length; i < index.current!.value; i++) {
+              fn.params[i] = t.identifier(path.scope.generateUid('param'));
+            }
             fn.params[index.current!.value] = varName.current!;
             path.remove();
             this.changes++;