fix(webpack/ast): Reduce if statements (swc-project#2969)

crates/swc_webpack_ast/Cargo.toml

@@ -5,7 +5,7 @@ edition = "2018"
 license = "Apache-2.0"
 name = "swc_webpack_ast"
 repository = "https://github.com/swc-project/swc.git"
-version = "0.5.0"
+version = "0.5.1"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 

crates/swc_webpack_ast/src/reducer.rs

@@ -1611,6 +1611,15 @@ impl VisitMut for ReduceAst {
                         return;
                     }
                 }
+
+                if is.cons.is_empty() && is.alt.is_empty() {
+                    self.changed = true;
+                    *stmt = Stmt::Expr(ExprStmt {
+                        span: DUMMY_SP,
+                        expr: is.test.take(),
+                    });
+                    return;
+                }
             }
 
             Stmt::While(s) => {

crates/swc_webpack_ast/tests/fixture.rs

@@ -46,6 +46,12 @@ impl VisitMut for AssertValid {
             panic!("found an identifier with dummy span: {:?}", i)
         }
     }
+
+    fn visit_mut_module(&mut self, m: &mut Module) {
+        dbg!(&*m);
+
+        m.visit_mut_children_with(self);
+    }
 }
 
 #[testing::fixture("../swc_ecma_parser/tests/typescript/tsc/**/input.ts")]
@@ -84,7 +90,6 @@ fn assert_no_invalid(input: PathBuf) {
         };
 
         module.visit_mut_with(&mut pass);
-        dbg!(&module);
         module.visit_mut_with(&mut AssertValid);
 
         Ok(())