fix(es/minifier): typeof class should be function (#9522)

**Related issue:** Closes #9453
swc-project · Sep 3, 2024 · c7fdd6b · c7fdd6b
1 parent 6bdc4f7
commit c7fdd6b
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Showing 5 changed files with 19 additions and 6 deletions.
diff --git a/.changeset/six-hounds-hammer.md b/.changeset/six-hounds-hammer.md
@@ -0,0 +1,6 @@
+---
+swc_core: patch
+swc_ecma_minifier: patch
+---
+
+fix(es/minifier): typeof class should be function rather than object
diff --git a/crates/swc_ecma_minifier/src/compress/optimize/inline.rs b/crates/swc_ecma_minifier/src/compress/optimize/inline.rs
@@ -156,7 +156,7 @@ impl Optimizer<'_> {
 
             if !usage.reassigned {
                 match init {
-                    Expr::Fn(..) | Expr::Arrow(..) => {
+                    Expr::Fn(..) | Expr::Arrow(..) | Expr::Class(..) => {
                         self.typeofs.insert(ident.to_id(), "function".into());
                     }
                     Expr::Array(..) | Expr::Object(..) => {
@@ -569,12 +569,9 @@ impl Optimizer<'_> {
             if !usage.reassigned {
                 trace_op!("typeofs: Storing typeof `{}{:?}`", i.sym, i.ctxt);
                 match &*decl {
-                    Decl::Fn(..) => {
+                    Decl::Fn(..) | Decl::Class(..) => {
                         self.typeofs.insert(i.to_id(), "function".into());
                     }
-                    Decl::Class(..) => {
-                        self.typeofs.insert(i.to_id(), "object".into());
-                    }
                     _ => {}
                 }
             }

diff --git a/crates/swc_ecma_minifier/src/compress/optimize/ops.rs b/crates/swc_ecma_minifier/src/compress/optimize/ops.rs
@@ -370,7 +370,7 @@ impl Optimizer<'_> {
                     }
                 }
 
-                Expr::Arrow(..) | Expr::Fn(..) => {
+                Expr::Arrow(..) | Expr::Fn(..) | Expr::Class(..) => {
                     report_change!("Converting typeof to 'function' as we know the value");
                     self.changed = true;
                     *e = Lit::Str(Str {

diff --git a/crates/swc_ecma_minifier/tests/fixture/issues/9453/input.js b/crates/swc_ecma_minifier/tests/fixture/issues/9453/input.js
@@ -0,0 +1,8 @@
+"use strict";
+class x {}
+const y = x;
+const z = class {};
+console.log(typeof x);
+console.log(typeof y);
+console.log(typeof z);
+console.log(typeof class {});
diff --git a/crates/swc_ecma_minifier/tests/fixture/issues/9453/output.js b/crates/swc_ecma_minifier/tests/fixture/issues/9453/output.js
@@ -0,0 +1,2 @@
+"use strict";
+console.log("function"), console.log("function"), console.log("function"), console.log("function");