fix(es/minifier): Don't remove exports (#7856)

Author: lewisl9029

crates/swc_ecma_minifier/src/compress/optimize/mod.rs

@@ -318,6 +318,10 @@ impl From<&Function> for FnMetadata {
 
 impl Optimizer<'_> {
     fn may_remove_ident(&self, id: &Ident) -> bool {
+        if self.ctx.is_exported {
+            return false;
+        }
+
         if id.span.ctxt != self.marks.top_level_ctxt {
             return true;
         }

crates/swc_ecma_minifier/tests/fixture/pr/7856/1/input.js

@@ -0,0 +1,4 @@
+const a = () => "";
+const b = {};
+export const c = a;
+b.c = c;

crates/swc_ecma_minifier/tests/fixture/pr/7856/1/output.js

@@ -0,0 +1 @@
+export const c = ()=>"";

crates/swc_ecma_minifier/tests/fixture/pr/7856/2/input.js

@@ -0,0 +1,5 @@
+export const a = 4;
+export const b = 16;
+export const c = 5;
+
+export const d = () => a;

crates/swc_ecma_minifier/tests/fixture/pr/7856/2/output.js

@@ -0,0 +1,4 @@
+export const a = 4;
+export const b = 16;
+export const c = 5;
+export const d = ()=>4;