Implement --drop (#14492)

Co-authored-by: dave caruso <me@paperdave.net>

docs/bundler/index.md

@@ -1130,6 +1130,26 @@ $ bun build ./index.tsx --outdir ./out --footer="// built with love in SF"
 
 {% /codetabs %}
 
+### `drop`
+
+Remove function calls from a bundle. For example, `--drop=console` will remove all calls to `console.log`. Arguments to calls will also be removed, regardless of if those arguments may have side effects. Dropping `debugger` will remove all `debugger` statements.
+
+{% codetabs %}
+
+```ts#JavaScript
+await Bun.build({
+  entrypoints: ['./index.tsx'],
+  outdir: './out',
+  drop: ["console", "debugger", "anyIdentifier.or.propertyAccess"],
+})
+```
+
+```bash#CLI
+$ bun build ./index.tsx --outdir ./out --drop=console --drop=debugger --drop=anyIdentifier.or.propertyAccess
+```
+
+{% /codetabs %}
+
 ### `experimentalCss`
 
 Whether to enable _experimental_ support for bundling CSS files. Defaults to `false`.

docs/bundler/vs-esbuild.md

@@ -190,8 +190,7 @@ In Bun's CLI, simple boolean flags like `--minify` do not accept an argument. Ot
 ---
 
 - `--drop`
-- n/a
-- Not supported
+- `--drop`
 
 ---
 

packages/bun-types/bun.d.ts

@@ -1612,6 +1612,11 @@ declare module "bun" {
      * Enable CSS support.
      */
     experimentalCss?: boolean;
+
+    /**
+     * Drop function calls to matching property accesses.
+     */
+    drop?: string[];
   }
 
   namespace Password {

src/api/schema.zig

@@ -1635,6 +1635,8 @@ pub const Api = struct {
         /// define
         define: ?StringMap = null,
 
+        drop: []const []const u8 = &.{},
+
         /// preserve_symlinks
         preserve_symlinks: ?bool = null,
 

src/bun.js/api/BunObject.zig

@@ -590,7 +590,7 @@ pub fn inspect(
 
     // we are going to always clone to keep things simple for now
     // the common case here will be stack-allocated, so it should be fine
-    var out = ZigString.init(array.toOwnedSliceLeaky()).withEncoding();
+    var out = ZigString.init(array.slice()).withEncoding();
     const ret = out.toJS(globalThis);
     array.deinit();
     return ret;
@@ -3932,7 +3932,7 @@ const TOMLObject = struct {
             return .zero;
         };
 
-        const slice = writer.ctx.buffer.toOwnedSliceLeaky();
+        const slice = writer.ctx.buffer.slice();
         var out = bun.String.fromUTF8(slice);
         defer out.deref();
 

src/bun.js/api/JSBundler.zig

@@ -75,6 +75,7 @@ pub const JSBundler = struct {
         banner: OwnedString = OwnedString.initEmpty(bun.default_allocator),
         footer: OwnedString = OwnedString.initEmpty(bun.default_allocator),
         experimental_css: bool = false,
+        drop: bun.StringSet = bun.StringSet.init(bun.default_allocator),
 
         pub const List = bun.StringArrayHashMapUnmanaged(Config);
 
@@ -191,7 +192,6 @@ pub const JSBundler = struct {
                 try this.banner.appendSliceExact(slice.slice());
             }
 
-
             if (try config.getOptional(globalThis, "footer", ZigString.Slice)) |slice| {
                 defer slice.deinit();
                 try this.footer.appendSliceExact(slice.slice());
@@ -351,6 +351,18 @@ pub const JSBundler = struct {
                 }
             }
 
+            if (try config.getOwnArray(globalThis, "drop")) |drops| {
+                var iter = drops.arrayIterator(globalThis);
+                while (iter.next()) |entry| {
+                    var slice = entry.toSliceOrNull(globalThis) orelse {
+                        globalThis.throwInvalidArguments("Expected drop to be an array of strings", .{});
+                        return error.JSError;
+                    };
+                    defer slice.deinit();
+                    try this.drop.insert(slice.slice());
+                }
+            }
+
             // if (try config.getOptional(globalThis, "dir", ZigString.Slice)) |slice| {
             //     defer slice.deinit();
             //     this.appendSliceExact(slice.slice()) catch unreachable;
@@ -544,6 +556,9 @@ pub const JSBundler = struct {
             self.rootdir.deinit();
             self.public_path.deinit();
             self.conditions.deinit();
+            self.drop.deinit();
+            self.banner.deinit();
+            self.footer.deinit();
         }
     };
 

src/bun.js/api/html_rewriter.zig

@@ -710,7 +710,7 @@ pub const HTMLRewriter = struct {
 
     //     pub fn done(this: *StreamOutputSink) void {
     //         var prev_value = this.response.body.value;
-    //         var bytes = this.bytes.toOwnedSliceLeaky();
+    //         var bytes = this.bytes.slice();
     //         this.response.body.value = .{
     //             .Blob = JSC.WebCore.Blob.init(bytes, this.bytes.allocator, this.global),
     //         };

src/bun.js/bindings/bindings.zig

@@ -3129,7 +3129,7 @@ pub const JSGlobalObject = opaque {
                 return ZigString.static(fmt).toErrorInstance(this);
 
             // Ensure we clone it.
-            var str = ZigString.initUTF8(buf.toOwnedSliceLeaky());
+            var str = ZigString.initUTF8(buf.slice());
 
             return str.toErrorInstance(this);
         } else {
@@ -3148,7 +3148,7 @@ pub const JSGlobalObject = opaque {
             defer buf.deinit();
             var writer = buf.writer();
             writer.print(fmt, args) catch return ZigString.static(fmt).toErrorInstance(this);
-            var str = ZigString.fromUTF8(buf.toOwnedSliceLeaky());
+            var str = ZigString.fromUTF8(buf.slice());
             return str.toTypeErrorInstance(this);
         } else {
             return ZigString.static(fmt).toTypeErrorInstance(this);
@@ -3162,7 +3162,7 @@ pub const JSGlobalObject = opaque {
             defer buf.deinit();
             var writer = buf.writer();
             writer.print(fmt, args) catch return ZigString.static(fmt).toErrorInstance(this);
-            var str = ZigString.fromUTF8(buf.toOwnedSliceLeaky());
+            var str = ZigString.fromUTF8(buf.slice());
             return str.toSyntaxErrorInstance(this);
         } else {
             return ZigString.static(fmt).toSyntaxErrorInstance(this);
@@ -3176,7 +3176,7 @@ pub const JSGlobalObject = opaque {
             defer buf.deinit();
             var writer = buf.writer();
             writer.print(fmt, args) catch return ZigString.static(fmt).toErrorInstance(this);
-            var str = ZigString.fromUTF8(buf.toOwnedSliceLeaky());
+            var str = ZigString.fromUTF8(buf.slice());
             return str.toRangeErrorInstance(this);
         } else {
             return ZigString.static(fmt).toRangeErrorInstance(this);
@@ -4619,7 +4619,7 @@ pub const JSValue = enum(JSValueReprInt) {
 
         var writer = buf.writer();
         try writer.print(fmt, args);
-        return String.init(buf.toOwnedSliceLeaky()).toJS(globalThis);
+        return String.init(buf.slice()).toJS(globalThis);
     }
 
     /// Create a JSValue string from a zig format-print (fmt + args), with pretty format
@@ -4633,7 +4633,7 @@ pub const JSValue = enum(JSValueReprInt) {
         switch (Output.enable_ansi_colors) {
             inline else => |enabled| try writer.print(Output.prettyFmt(fmt, enabled), args),
         }
-        return String.init(buf.toOwnedSliceLeaky()).toJS(globalThis);
+        return String.init(buf.slice()).toJS(globalThis);
     }
 
     pub fn fromEntries(globalThis: *JSGlobalObject, keys_array: [*c]ZigString, values_array: [*c]ZigString, strings_count: usize, clone: bool) JSValue {

src/bun.js/module_loader.zig

@@ -2143,7 +2143,7 @@ pub const ModuleLoader = struct {
                     writer.writeAll(";\n") catch bun.outOfMemory();
                 }
 
-                const public_url = bun.String.createUTF8(buf.toOwnedSliceLeaky());
+                const public_url = bun.String.createUTF8(buf.slice());
                 return ResolvedSource{
                     .allocator = &jsc_vm.allocator,
                     .source_code = public_url,

src/bun.js/test/diff_format.zig

@@ -129,8 +129,8 @@ pub const DiffFormatter = struct {
             buffered_writer.flush() catch unreachable;
         }
 
-        const received_slice = received_buf.toOwnedSliceLeaky();
-        const expected_slice = expected_buf.toOwnedSliceLeaky();
+        const received_slice = received_buf.slice();
+        const expected_slice = expected_buf.slice();
 
         if (this.not) {
             const not_fmt = "Expected: not <green>{s}<r>";

src/bun.js/test/expect.zig

@@ -2757,7 +2757,7 @@ pub const Expect = struct {
             };
             defer pretty_value.deinit();
 
-            if (strings.eqlLong(pretty_value.toOwnedSliceLeaky(), saved_value, true)) {
+            if (strings.eqlLong(pretty_value.slice(), saved_value, true)) {
                 Jest.runner.?.snapshots.passed += 1;
                 return .undefined;
             }
@@ -2766,7 +2766,7 @@ pub const Expect = struct {
             const signature = comptime getSignature("toMatchSnapshot", "<green>expected<r>", false);
             const fmt = signature ++ "\n\n{any}\n";
             const diff_format = DiffFormatter{
-                .received_string = pretty_value.toOwnedSliceLeaky(),
+                .received_string = pretty_value.slice(),
                 .expected_string = saved_value,
                 .globalThis = globalThis,
             };
@@ -5443,7 +5443,7 @@ pub const ExpectCustomAsymmetricMatcher = struct {
             return .zero;
         };
         if (printed) {
-            return bun.String.init(mutable_string.toOwnedSliceLeaky()).toJS();
+            return bun.String.init(mutable_string.slice()).toJS();
         }
         return ExpectMatcherUtils.printValue(globalThis, this, null);
     }

src/bun.js/test/jest.zig

@@ -1788,7 +1788,7 @@ inline fn createScope(
                 buffer.reset();
                 appendParentLabel(&buffer, parent) catch @panic("Bun ran out of memory while filtering tests");
                 buffer.append(label) catch unreachable;
-                const str = bun.String.fromBytes(buffer.toOwnedSliceLeaky());
+                const str = bun.String.fromBytes(buffer.slice());
                 is_skip = !regex.matches(str);
                 if (is_skip) {
                     tag_to_use = .skip;
@@ -2087,7 +2087,7 @@ fn eachBind(
                 buffer.reset();
                 appendParentLabel(&buffer, parent) catch @panic("Bun ran out of memory while filtering tests");
                 buffer.append(formattedLabel) catch unreachable;
-                const str = bun.String.fromBytes(buffer.toOwnedSliceLeaky());
+                const str = bun.String.fromBytes(buffer.slice());
                 is_skip = !regex.matches(str);
             }
 

src/bun.js/web_worker.zig

@@ -331,7 +331,7 @@ pub const WebWorker = struct {
             bun.outOfMemory();
         };
         JSC.markBinding(@src());
-        WebWorker__dispatchError(globalObject, worker.cpp_worker, bun.String.createUTF8(array.toOwnedSliceLeaky()), error_instance);
+        WebWorker__dispatchError(globalObject, worker.cpp_worker, bun.String.createUTF8(array.slice()), error_instance);
         if (vm.worker) |worker_| {
             _ = worker.setRequestedTerminate();
             worker.parent_poll_ref.unrefConcurrently(worker.parent);

src/bundler/bundle_v2.zig

@@ -1439,7 +1439,7 @@ pub const BundleV2 = struct {
                     .entry_points = config.entry_points.keys(),
                     .target = config.target.toAPI(),
                     .absolute_working_dir = if (config.dir.list.items.len > 0)
-                        config.dir.toOwnedSliceLeaky()
+                        config.dir.slice()
                     else
                         null,
                     .inject = &.{},
@@ -1449,6 +1449,7 @@ pub const BundleV2 = struct {
                     .env_files = &.{},
                     .conditions = config.conditions.map.keys(),
                     .ignore_dce_annotations = bundler.options.ignore_dce_annotations,
+                    .drop = config.drop.map.keys(),
                 },
                 completion.env,
             );
@@ -1466,8 +1467,8 @@ pub const BundleV2 = struct {
             bundler.options.output_format = config.format;
             bundler.options.bytecode = config.bytecode;
 
-            bundler.options.output_dir = config.outdir.toOwnedSliceLeaky();
-            bundler.options.root_dir = config.rootdir.toOwnedSliceLeaky();
+            bundler.options.output_dir = config.outdir.slice();
+            bundler.options.root_dir = config.rootdir.slice();
             bundler.options.minify_syntax = config.minify.syntax;
             bundler.options.minify_whitespace = config.minify.whitespace;
             bundler.options.minify_identifiers = config.minify.identifiers;
@@ -1478,8 +1479,8 @@ pub const BundleV2 = struct {
             bundler.options.emit_dce_annotations = config.emit_dce_annotations orelse !config.minify.whitespace;
             bundler.options.ignore_dce_annotations = config.ignore_dce_annotations;
             bundler.options.experimental_css = config.experimental_css;
-            bundler.options.banner = config.banner.toOwnedSlice();
-            bundler.options.footer = config.footer.toOwnedSlice();
+            bundler.options.banner = config.banner.slice();
+            bundler.options.footer = config.footer.slice();
 
             bundler.configureLinker();
             try bundler.configureDefines();
@@ -1545,7 +1546,7 @@ pub const BundleV2 = struct {
                                     bun.default_allocator.dupe(
                                         u8,
                                         bun.path.joinAbsString(
-                                            this.config.outdir.toOwnedSliceLeaky(),
+                                            this.config.outdir.slice(),
                                             &[_]string{output_file.dest_path},
                                             .auto,
                                         ),
@@ -1555,7 +1556,7 @@ pub const BundleV2 = struct {
                                         u8,
                                         bun.path.joinAbsString(
                                             Fs.FileSystem.instance.top_level_dir,
-                                            &[_]string{ this.config.dir.toOwnedSliceLeaky(), this.config.outdir.toOwnedSliceLeaky(), output_file.dest_path },
+                                            &[_]string{ this.config.dir.slice(), this.config.outdir.slice(), output_file.dest_path },
                                             .auto,
                                         ),
                                     ) catch unreachable
@@ -8950,7 +8951,7 @@ pub const LinkerContext = struct {
                     const input = c.parse_graph.input_files.items(.source)[chunk.entry_point.source_index].path;
                     var buf = MutableString.initEmpty(worker.allocator);
                     js_printer.quoteForJSONBuffer(input.pretty, &buf, true) catch bun.outOfMemory();
-                    const str = buf.toOwnedSliceLeaky(); // worker.allocator is an arena
+                    const str = buf.slice(); // worker.allocator is an arena
                     j.pushStatic(str);
                     line_offset.advance(str);
                 }

src/cli.zig

@@ -194,10 +194,11 @@ pub const Arguments = struct {
     };
 
     const transpiler_params_ = [_]ParamType{
-        clap.parseParam("--main-fields <STR>...            Main fields to lookup in package.json. Defaults to --target dependent") catch unreachable,
+        clap.parseParam("--main-fields <STR>...             Main fields to lookup in package.json. Defaults to --target dependent") catch unreachable,
         clap.parseParam("--extension-order <STR>...        Defaults to: .tsx,.ts,.jsx,.js,.json ") catch unreachable,
-        clap.parseParam("--tsconfig-override <STR>         Specify custom tsconfig.json. Default <d>$cwd<r>/tsconfig.json") catch unreachable,
-        clap.parseParam("-d, --define <STR>...             Substitute K:V while parsing, e.g. --define process.env.NODE_ENV:\"development\". Values are parsed as JSON.") catch unreachable,
+        clap.parseParam("--tsconfig-override <STR>          Specify custom tsconfig.json. Default <d>$cwd<r>/tsconfig.json") catch unreachable,
+        clap.parseParam("-d, --define <STR>...              Substitute K:V while parsing, e.g. --define process.env.NODE_ENV:\"development\". Values are parsed as JSON.") catch unreachable,
+        clap.parseParam("--drop <STR>...                   Remove function calls, e.g. --drop=console removes all console.* calls.") catch unreachable,
         clap.parseParam("-l, --loader <STR>...             Parse files with .ext:loader, e.g. --loader .js:jsx. Valid loaders: js, jsx, ts, tsx, json, toml, text, file, wasm, napi") catch unreachable,
         clap.parseParam("--no-macros                       Disable macros from being executed in the bundler, transpiler and runtime") catch unreachable,
         clap.parseParam("--jsx-factory <STR>               Changes the function called when compiling JSX elements using the classic JSX runtime") catch unreachable,
@@ -590,6 +591,8 @@ pub const Arguments = struct {
             };
         }
 
+        opts.drop = args.options("--drop");
+
         const loader_tuple = try LoaderColonList.resolve(allocator, args.options("--loader"));
 
         if (loader_tuple.keys.len > 0) {

src/cli/build_command.zig

@@ -99,6 +99,7 @@ pub const BuildCommand = struct {
 
         this_bundler.options.banner = ctx.bundler_options.banner;
         this_bundler.options.footer = ctx.bundler_options.footer;
+        this_bundler.options.drop = ctx.args.drop;
 
         this_bundler.options.experimental_css = ctx.bundler_options.experimental_css;
 
@@ -236,10 +237,11 @@ pub const BuildCommand = struct {
                         allocator,
                         user_defines.keys,
                         user_defines.values,
-                    ), log, allocator)
+                    ), ctx.args.drop, log, allocator)
                 else
                     null,
                 null,
+                this_bundler.options.define.drop_debugger,
             );
 
             try bun.bake.addImportMetaDefines(allocator, this_bundler.options.define, .development, .server);

src/cli/upgrade_command.zig

@@ -559,7 +559,7 @@ pub const UpgradeCommand = struct {
                 else => return error.HTTPError,
             }
 
-            const bytes = zip_file_buffer.toOwnedSliceLeaky();
+            const bytes = zip_file_buffer.slice();
 
             progress.end();
             refresher.refresh();