Fix no-empty for contructors (denoland#152)

src/rules/no_empty.rs

@@ -1,6 +1,6 @@
 // Copyright 2020 the Deno authors. All rights reserved. MIT license.
 use super::{Context, LintRule};
-use swc_ecma_ast::{BlockStmt, Function, Module, SwitchStmt};
+use swc_ecma_ast::{BlockStmt, Constructor, Function, Module, SwitchStmt};
 use swc_ecma_visit::{Node, Visit};
 
 pub struct NoEmpty;
@@ -32,7 +32,7 @@ impl NoEmptyVisitor {
 
 impl Visit for NoEmptyVisitor {
   fn visit_function(&mut self, function: &Function, _parent: &dyn Node) {
-    // Empty functions shouldn't be caught be this rule.
+    // Empty functions shouldn't be caught by this rule.
     // Because function's body is a block statement, we're gonna
     // manually visit each member; otherwise rule would produce errors
     // for empty function body.
@@ -43,6 +43,15 @@ impl Visit for NoEmptyVisitor {
     }
   }
 
+  fn visit_constructor(&mut self, cons: &Constructor, _parent: &dyn Node) {
+    // Similar to the above, empty constructors shouldn't be caught.
+    if let Some(body) = &cons.body {
+      for stmt in &body.stmts {
+        swc_ecma_visit::visit_stmt(self, stmt, body);
+      }
+    }
+  }
+
   fn visit_block_stmt(&mut self, block_stmt: &BlockStmt, _parent: &dyn Node) {
     if block_stmt.stmts.is_empty() {
       if !block_stmt.contains_comments(&self.context) {
@@ -94,6 +103,17 @@ mod tests {
     assert_lint_ok::<NoEmpty>(r#"function foobar() {}"#);
   }
 
+  #[test]
+  fn it_passes_for_an_empty_constructor() {
+    assert_lint_ok::<NoEmpty>(
+      r#"
+class Foo {
+  constructor() {}
+}
+      "#,
+    );
+  }
+
   #[test]
   fn it_passes_for_a_non_empty_block() {
     assert_lint_ok::<NoEmpty>(r#"if (foo) { var bar = ""; }"#);