Implement --drop (#14492)

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

Author: Jarred-Sumner

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>";