More DCE

1 files changed, 34 insertions, 27 deletions

diff --git a/src/js_parser.zig b/src/js_parser.zig
index 4cab7ffdc..f78e5b160 100644
--- a/src/js_parser.zig
+++ b/src/js_parser.zig
@@ -1634,29 +1634,25 @@ pub const SideEffects = enum(u1) {
             },
 
             .e_object => {
-                // Arrays with "..." spread expressions can't be unwrapped because the
-                // "..." triggers code evaluation via iterators. In that case, just trim
-                // the other items instead and leave the array expression there.
-
+                // Objects with "..." spread expressions can't be unwrapped because the
+                // "..." triggers code evaluation via getters. In that case, just trim
+                // the other items instead and leave the object expression there.
                 var properties_slice = expr.data.e_object.properties.slice();
                 var end: usize = 0;
-                var any_computed = false;
                 for (properties_slice) |spread| {
                     end = 0;
-                    any_computed = any_computed or spread.flags.contains(.is_computed);
                     if (spread.kind == .spread) {
                         // Spread properties must always be evaluated
                         for (properties_slice) |prop_| {
                             var prop = prop_;
                             if (prop_.kind != .spread) {
-                                if (prop.value != null) {
-                                    if (simpifyUnusedExpr(p, prop.value.?)) |value| {
-                                        prop.value = value;
-                                    } else if (!prop.flags.contains(.is_computed)) {
-                                        continue;
-                                    } else {
-                                        prop.value = p.newExpr(E.Number{ .value = 0.0 }, prop.value.?.loc);
-                                    }
+                                var value = simpifyUnusedExpr(p, prop.value.?);
+                                if (value != null) {
+                                    prop.value = value;
+                                } else if (!prop.flags.contains(.is_computed)) {
+                                    continue;
+                                } else {
+                                    prop.value = p.newExpr(E.Number{ .value = 0.0 }, prop.value.?.loc);
                                 }
                             }
 
@@ -1670,21 +1666,32 @@ pub const SideEffects = enum(u1) {
                     }
                 }
 
-                if (any_computed) {
-                    // Otherwise, the object can be completely removed. We only need to keep any
-                    // object properties with side effects. Apply this simplification recursively.
-                    // for (properties_slice) |prop| {
-                    //     if (prop.flags.is_computed) {
-                    //         // Make sure "ToString" is still evaluated on the key
+                var result = Expr.init(E.Missing, E.Missing{}, expr.loc);
 
-                    //     }
-                    // }
-
-                    // keep this for now because we need better test coverage to do this correctly
-                    return expr;
+                // Otherwise, the object can be completely removed. We only need to keep any
+                // object properties with side effects. Apply this simplification recursively.
+                for (properties_slice) |prop| {
+                    if (prop.flags.contains(.is_computed)) {
+                        // Make sure "ToString" is still evaluated on the key
+                        result = result.joinWithComma(
+                            p.newExpr(
+                                E.Binary{
+                                    .op = .bin_add,
+                                    .left = prop.key.?,
+                                    .right = p.newExpr(E.String{}, prop.key.?.loc),
+                                },
+                                prop.key.?.loc,
+                            ),
+                            p.allocator,
+                        );
+                    }
+                    result = result.joinWithComma(
+                        simpifyUnusedExpr(p, prop.value.?) orelse prop.value.?.toEmpty(),
+                        p.allocator,
+                    );
                 }
 
-                return null;
+                return result;
             },
             .e_array => {
                 var items = expr.data.e_array.items.slice();
@@ -16879,7 +16886,7 @@ fn NewParser_(
                     for (ex.properties.slice()) |*property| {
 
                         // The key must still be evaluated if it's computed or a spread
-                        if (property.kind == .spread or property.flags.contains(.is_computed) or property.flags.contains(.is_spread)) {
+                        if (property.kind == .spread or (property.flags.contains(.is_computed) and !property.key.?.isPrimitiveLiteral()) or property.flags.contains(.is_spread)) {
                             return false;
                         }