'let' statements before using statements are now properly converted i…

…nto 'var' statements (oven-sh#14260)
karlhorky · Oct 10, 2024 · ff47631 · ff47631
1 parent def454d
commit ff47631
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Showing 3 changed files with 25 additions and 15 deletions.
diff --git a/src/js_parser.zig b/src/js_parser.zig
@@ -19430,6 +19430,7 @@ fn NewParser_(
                         }
                     }
 
+                    data.kind = kind;
                     try stmts.append(stmt.*);
 
                     if (p.options.features.react_fast_refresh and p.current_scope == p.module_scope) {
@@ -22155,29 +22156,37 @@ fn NewParser_(
                         switch (stmt.data) {
                             .s_empty, .s_comment, .s_directive, .s_debugger, .s_type_script => continue,
                             .s_local => |local| {
-                                if (!local.is_export and local.kind == .k_const and !local.was_commonjs_export) {
+                                if (!local.is_export and !local.was_commonjs_export) {
                                     var decls: []Decl = local.decls.slice();
                                     var end: usize = 0;
+                                    var any_decl_in_const_values = local.kind == .k_const;
                                     for (decls) |decl| {
                                         if (decl.binding.data == .b_identifier) {
-                                            const symbol = p.symbols.items[decl.binding.data.b_identifier.ref.innerIndex()];
-                                            if (p.const_values.contains(decl.binding.data.b_identifier.ref) and symbol.use_count_estimate == 0) {
-                                                continue;
+                                            if (p.const_values.contains(decl.binding.data.b_identifier.ref)) {
+                                                any_decl_in_const_values = true;
+                                                const symbol = p.symbols.items[decl.binding.data.b_identifier.ref.innerIndex()];
+                                                if (symbol.use_count_estimate == 0) {
+                                                    // Skip declarations that are constants with zero usage
+                                                    continue;
+                                                }
                                             }
                                         }
                                         decls[end] = decl;
                                         end += 1;
                                     }
                                     local.decls.len = @as(u32, @truncate(end));
-                                    if (end == 0) {
-                                        stmt.* = stmt.*.toEmpty();
+                                    if (any_decl_in_const_values) {
+                                        if (end == 0) {
+                                            stmt.* = stmt.*.toEmpty();
+                                        }
+                                        continue;
                                     }
-                                    continue;
                                 }
                             },
                             else => {},
                         }
 
+                        // Break after processing relevant statements
                         break;
                     }
                 }

diff --git a/test/bundler/bundler_edgecase.test.ts b/test/bundler/bundler_edgecase.test.ts
@@ -1121,7 +1121,7 @@ describe("bundler", () => {
     snapshotSourceMap: {
       "entry.js.map": {
         files: ["../node_modules/react/index.js", "../entry.js"],
-        mappingsExactMatch: "uYACA,WAAW,IAAQ,EAAE,ICDrB,eACA,QAAQ,IAAI,CAAK",
+        mappingsExactMatch: "qYACA,WAAW,IAAQ,EAAE,ICDrB,eACA,QAAQ,IAAI,CAAK",
       },
     },
   });
@@ -1883,6 +1883,7 @@ describe("bundler", () => {
     target: "browser",
     run: { stdout: `123` },
   });
+
   itBundled("edgecase/UninitializedVariablesMoved", {
     files: {
       "/entry.ts": `

diff --git a/test/bundler/bundler_npm.test.ts b/test/bundler/bundler_npm.test.ts
@@ -57,17 +57,17 @@ describe("bundler", () => {
           "../entry.tsx",
         ],
         mappings: [
-          ["react.development.js:524:'getContextName'", "1:5428:Y1"],
-          ["react.development.js:2495:'actScopeDepth'", "1:26053:GJ++"],
-          ["react.development.js:696:''Component'", '1:7490:\'Component "%s"'],
-          ["entry.tsx:6:'\"Content-Type\"'", '1:221655:"Content-Type"'],
-          ["entry.tsx:11:'<html>'", "1:221911:void"],
-          ["entry.tsx:23:'await'", "1:222013:await"],
+          ["react.development.js:524:'getContextName'", "1:5426:Y1"],
+          ["react.development.js:2495:'actScopeDepth'", "1:26051:GJ++"],
+          ["react.development.js:696:''Component'", '1:7488:\'Component "%s"'],
+          ["entry.tsx:6:'\"Content-Type\"'", '1:221651:"Content-Type"'],
+          ["entry.tsx:11:'<html>'", "1:221905:void"],
+          ["entry.tsx:23:'await'", "1:222005:await"],
         ],
       },
     },
     expectExactFilesize: {
-      "out/entry.js": 222283,
+      "out/entry.js": 222273,
     },
     run: {
       stdout: "<!DOCTYPE html><html><body><h1>Hello World</h1><p>This is an example.</p></body></html>",