Fix block removal during early continue transform (#623)

* Fix block removal during early continue transform

+ Fix #560

* Fix test suite

Author: boopathi

packages/babel-plugin-minify-simplify/__tests__/simplify-test.js

@@ -2512,4 +2512,24 @@ describe("simplify-plugin", () => {
     const b = () => {};
   `
   );
+
+  thePlugin(
+    "should NOT remove block for early continue transforms - fix issue#560",
+    `
+      function foo() {
+        while (true) {
+          const {x} = a;
+          const {y} = b;
+        }
+      }
+    `,
+    `
+      function foo() {
+        for (; true;) {
+          const { x } = a;
+          const { y } = b;
+        }
+      }
+    `
+  );
 });

packages/babel-plugin-minify-simplify/src/index.js

@@ -1519,7 +1519,8 @@ module.exports = ({ types: t }) => {
       t.isTryStatement(parent) ||
       t.isCatchClause(parent) ||
       t.isSwitchStatement(parent) ||
-      (isSingleBlockScopeDeclaration(node) && t.isIfStatement(parent))
+      (isSingleBlockScopeDeclaration(node) &&
+        (t.isIfStatement(parent) || t.isLoop(parent)))
     );
   }
 
@@ -1581,7 +1582,7 @@ module.exports = ({ types: t }) => {
     }
 
     // We may have reduced the body to a single statement.
-    if (node.body.body.length === 1) {
+    if (node.body.body.length === 1 && !needsBlock(node.body, node)) {
       path.get("body").replaceWith(node.body.body[0]);
     }
   }