fix(es/minifier): Do not drop used properties

crates/swc/tests/fixture/issues-7xxx/7700/input/.swcrc

@@ -0,0 +1,66 @@
+{
+    "jsc": {
+        "parser": {
+            "syntax": "typescript",
+            "tsx": true
+        },
+        "transform": {
+            "react": {}
+        },
+        "target": "es5",
+        "loose": true,
+        "minify": {
+            "compress": {
+                "arguments": false,
+                "arrows": true,
+                "booleans": true,
+                "booleans_as_integers": false,
+                "collapse_vars": true,
+                "comparisons": true,
+                "computed_props": true,
+                "conditionals": true,
+                "dead_code": true,
+                "directives": true,
+                "drop_console": false,
+                "drop_debugger": true,
+                "evaluate": true,
+                "expression": false,
+                "hoist_funs": false,
+                "hoist_props": true,
+                "hoist_vars": false,
+                "if_return": true,
+                "join_vars": true,
+                "keep_classnames": false,
+                "keep_fargs": true,
+                "keep_fnames": false,
+                "keep_infinity": false,
+                "loops": true,
+                "negate_iife": true,
+                "properties": true,
+                "reduce_funcs": false,
+                "reduce_vars": false,
+                "side_effects": true,
+                "switches": true,
+                "typeofs": true,
+                "unsafe": false,
+                "unsafe_arrows": false,
+                "unsafe_comps": false,
+                "unsafe_Function": false,
+                "unsafe_math": false,
+                "unsafe_symbols": false,
+                "unsafe_methods": false,
+                "unsafe_proto": false,
+                "unsafe_regexp": false,
+                "unsafe_undefined": false,
+                "unused": true,
+                "const_to_let": true,
+                "pristine_globals": true
+            }
+        },
+    },
+    "isModule": true,
+    "module": {
+        "type": "commonjs"
+    },
+    "minify": false
+}

crates/swc/tests/fixture/issues-7xxx/7700/input/1.js

@@ -0,0 +1,27 @@
+interface IProps {
+    isRtl: boolean | string;
+    position: keyof typeof positions;
+}
+
+const positions = {
+    top: 1,
+    left: 2,
+    right: 3,
+    bottom: 4,
+}
+
+const rtlPositions = {
+    top: 1,
+    right: 2,
+    left: 3,
+    bottom: 4,
+}
+
+export function PositionRender({ isRtl, position }: IProps) {
+
+    const display = (isRtl === 'fe-fe-fe' ? rtlPositions : positions)[position];
+
+    return <h1>
+        PositionRender: {display}
+    </h1>
+}

crates/swc_ecma_usage_analyzer/src/analyzer/mod.rs

@@ -306,7 +306,7 @@ where
             self.with_ctx(ctx).visit_in_cond(&e.right);
         } else {
             if e.op == op!("in") {
-                if let Expr::Ident(obj) = &*e.right {
+                for_each_id_ref_in_expr(&e.right, &mut |obj| {
                     let var = self.data.var_or_default(obj.to_id());
 
                     match &*e.left {
@@ -318,7 +318,7 @@ where
                             var.mark_indexed_with_dynamic_key();
                         }
                     }
-                }
+                })
             }
 
             let ctx = Ctx {
@@ -354,11 +354,11 @@ where
         }
 
         if let Callee::Expr(callee) = &n.callee {
-            if let Expr::Ident(callee) = &**callee {
+            for_each_id_ref_in_expr(callee, &mut |callee| {
                 self.data
                     .var_or_default(callee.to_id())
                     .mark_used_as_callee();
-            }
+            });
 
             match &**callee {
                 Expr::Fn(callee) => {
@@ -419,9 +419,9 @@ where
         }
 
         for arg in &n.args {
-            if let Expr::Ident(arg) = &*arg.expr {
+            for_each_id_ref_in_expr(&arg.expr, &mut |arg| {
                 self.data.var_or_default(arg.to_id()).mark_used_as_arg();
-            }
+            })
         }
 
         if let Callee::Expr(callee) = &n.callee {
@@ -644,11 +644,11 @@ where
         e.visit_children_with(self);
 
         if e.spread.is_some() {
-            if let Expr::Ident(i) = &*e.expr {
+            for_each_id_ref_in_expr(&e.expr, &mut |i| {
                 self.data
                     .var_or_default(i.to_id())
                     .mark_indexed_with_dynamic_key();
-            }
+            });
         }
     }
 
@@ -873,7 +873,7 @@ where
             };
             c.visit_with(&mut *self.with_ctx(ctx));
         }
-        if let Expr::Ident(obj) = &*e.obj {
+        for_each_id_ref_in_expr(&e.obj, &mut |obj| {
             let v = self.data.var_or_default(obj.to_id());
             v.mark_has_property_access();
 
@@ -892,7 +892,7 @@ where
             if self.ctx.in_assign_lhs || self.ctx.is_delete_arg {
                 self.data.mark_property_mutattion(obj.to_id(), self.ctx)
             }
-        }
+        })
     }
 
     #[cfg_attr(feature = "debug", tracing::instrument(skip(self, n)))]
@@ -1065,11 +1065,11 @@ where
     fn visit_spread_element(&mut self, e: &SpreadElement) {
         e.visit_children_with(self);
 
-        if let Expr::Ident(i) = &*e.expr {
+        for_each_id_ref_in_expr(&e.expr, &mut |i| {
             self.data
                 .var_or_default(i.to_id())
                 .mark_indexed_with_dynamic_key();
-        }
+        });
     }
 
     #[cfg_attr(feature = "debug", tracing::instrument(skip(self, n)))]
@@ -1307,6 +1307,22 @@ where
     }
 }
 
+/// - `a` => `a`
+/// - `a ? b : c` => `b`, `c`
+fn for_each_id_ref_in_expr(e: &Expr, op: &mut impl FnMut(&Ident)) {
+    match e {
+        Expr::Ident(i) => op(i),
+        Expr::Cond(c) => {
+            for_each_id_ref_in_expr(&c.cons, op);
+            for_each_id_ref_in_expr(&c.alt, op);
+        }
+        Expr::Seq(s) => {
+            for_each_id_ref_in_expr(s.exprs.last().unwrap(), op);
+        }
+        _ => {}
+    }
+}
+
 fn leftmost(p: &Expr) -> Option<Id> {
     match p {
         Expr::Ident(i) => Some(i.to_id()),