fix(es/codegen): Emit declare keyword for class properties (#8478)

crates/swc_ecma_codegen/src/lib.rs

@@ -1606,6 +1606,11 @@ where
             emit!(dec)
         }
 
+        if n.declare {
+            keyword!("declare");
+            space!();
+        }
+
         self.emit_accessibility(n.accessibility)?;
 
         if n.is_static {

crates/swc_ecma_codegen/tests/fixture/typescript/class_prop/input.js

@@ -7,4 +7,5 @@ class MyClass extends Base {
     readonly #prop6 = "asdf";
     public abstract override readonly prop7 = 5;
     override readonly #prop8 = 5;
+    declare public static readonly prop9: string;
 }

crates/swc_ecma_codegen/tests/fixture/typescript/class_prop/output.js

@@ -7,4 +7,5 @@ class MyClass extends Base {
     readonly #prop6 = "asdf";
     public abstract override readonly prop7 = 5;
     override readonly #prop8 = 5;
+    declare public static readonly prop9: string;
 }

crates/swc_ecma_codegen/tests/fixture/typescript/class_prop/output.min.js

@@ -1 +1 @@
-class MyClass extends Base{prop1?: string;prop2!: string;#prop3?: string;#prop4?: string="test";static readonly prop5!: string;readonly #prop6="asdf";public abstract override readonly prop7=5;override readonly #prop8=5}
+class MyClass extends Base{prop1?: string;prop2!: string;#prop3?: string;#prop4?: string="test";static readonly prop5!: string;readonly #prop6="asdf";public abstract override readonly prop7=5;override readonly #prop8=5;declare public static readonly prop9: string}

crates/swc_ecma_transforms_typescript/src/strip_type.rs

@@ -143,6 +143,7 @@ impl VisitMut for StripType {
     }
 
     fn visit_mut_class_prop(&mut self, prop: &mut ClassProp) {
+        prop.declare = false;
         prop.readonly = false;
         prop.is_override = false;
         prop.is_optional = false;