feat(es/codegen): Support preamble (#7551)

**Related issue:** - Closes #7475.
swc-project · Jun 20, 2023 · 6e5d8b3 · 6e5d8b3 · github-actions · Jun 20, 2023
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Showing 17 changed files with 118 additions and 3 deletions.
diff --git a/bindings/binding_core_node/src/bundle.rs b/bindings/binding_core_node/src/bundle.rs
@@ -138,6 +138,7 @@ impl Task for BundleTask {
                                 None,
                                 true,
                                 false,
+                                Default::default(),
                             )?;
 
                             Ok((k, output))

diff --git a/bindings/binding_core_node/src/print.rs b/bindings/binding_core_node/src/print.rs
@@ -51,6 +51,7 @@ impl Task for PrintTask {
                     None,
                     options.config.emit_source_map_columns.into_bool(),
                     false,
+                    Default::default(),
                 )
                 .convert_err()
         })
@@ -112,6 +113,7 @@ pub fn print_sync(program: String, options: Buffer) -> napi::Result<TransformOut
             None,
             options.config.emit_source_map_columns.into_bool(),
             false,
+            Default::default(),
         )
         .convert_err()
     })

diff --git a/crates/binding_macros/src/wasm.rs b/crates/binding_macros/src/wasm.rs
@@ -258,6 +258,7 @@ macro_rules! build_print_sync {
                         None,
                         opts.config.emit_source_map_columns.into_bool(),
                         false,
+                        Default::default(),
                     ),"failed to print code")?;
 
                     serde_wasm_bindgen::to_value(&s)

diff --git a/crates/swc/benches/typescript.rs b/crates/swc/benches/typescript.rs
@@ -123,6 +123,7 @@ fn bench_codegen(b: &mut Bencher, _target: EsVersion) {
                     None,
                     false,
                     false,
+                    Default::default(),
                 )
                 .unwrap()
             }));

diff --git a/crates/swc/src/config/mod.rs b/crates/swc/src/config/mod.rs
@@ -612,6 +612,15 @@ impl Options {
             }
         });
 
+        let preamble = if !cfg.jsc.output.preamble.is_empty() {
+            cfg.jsc.output.preamble
+        } else {
+            js_minify
+                .as_ref()
+                .map(|v| v.format.preamble.clone())
+                .unwrap_or_default()
+        };
+
         let pass = PassBuilder::new(
             cm,
             handler,
@@ -842,7 +851,7 @@ impl Options {
             comments: comments.cloned(),
             preserve_comments,
             emit_source_map_columns: cfg.emit_source_map_columns.into_bool(),
-            output: JscOutputConfig { charset },
+            output: JscOutputConfig { charset, preamble },
         })
     }
 }
@@ -1401,6 +1410,9 @@ pub struct JscConfig {
 pub struct JscOutputConfig {
     #[serde(default)]
     pub charset: Option<OutputCharset>,
+
+    #[serde(default)]
+    pub preamble: String,
 }
 
 #[derive(Debug, Clone, Serialize, Deserialize)]

diff --git a/crates/swc/src/lib.rs b/crates/swc/src/lib.rs
@@ -506,6 +506,7 @@ impl Compiler {
         comments: Option<&dyn Comments>,
         emit_source_map_columns: bool,
         ascii_only: bool,
+        preamble: &str,
     ) -> Result<TransformOutput, Error>
     where
         T: Node + VisitWith<IdentCollector>,
@@ -518,7 +519,7 @@ impl Compiler {
             let src = {
                 let mut buf = vec![];
                 {
-                    let mut wr = Box::new(swc_ecma_codegen::text_writer::JsWriter::new(
+                    let mut w = swc_ecma_codegen::text_writer::JsWriter::new(
                         self.cm.clone(),
                         "\n",
                         &mut buf,
@@ -527,7 +528,9 @@ impl Compiler {
                         } else {
                             None
                         },
-                    )) as Box<dyn WriteJs>;
+                    );
+                    w.preamble(preamble).unwrap();
+                    let mut wr = Box::new(w) as Box<dyn WriteJs>;
 
                     if minify {
                         wr = Box::new(swc_ecma_codegen::text_writer::omit_trailing_semi(wr));
@@ -1158,6 +1161,7 @@ impl Compiler {
                 Some(&comments),
                 opts.emit_source_map_columns,
                 opts.format.ascii_only,
+                &opts.format.preamble,
             )
         })
     }
@@ -1236,6 +1240,7 @@ impl Compiler {
                     .charset
                     .map(|v| matches!(v, OutputCharset::Ascii))
                     .unwrap_or(false),
+                &config.output.preamble,
             )
         })
     }

diff --git a/crates/swc/tests/minify/issue-7475/1-with-preamble/config.json b/crates/swc/tests/minify/issue-7475/1-with-preamble/config.json
@@ -0,0 +1,5 @@
+{
+    "format": {
+        "preamble": "/** @license */\n"
+    }
+}
diff --git a/crates/swc/tests/minify/issue-7475/1-with-preamble/input.js b/crates/swc/tests/minify/issue-7475/1-with-preamble/input.js
@@ -0,0 +1,5 @@
+function foo() {
+    console.log('Foo')
+}
+
+foo()
diff --git a/crates/swc/tests/minify/issue-7475/1-with-preamble/output.js b/crates/swc/tests/minify/issue-7475/1-with-preamble/output.js
@@ -0,0 +1,2 @@
+/** @license */
+function foo(){console.log("Foo")}foo();
diff --git a/crates/swc/tests/minify/issue-7475/1-with-preamble/output.map b/crates/swc/tests/minify/issue-7475/1-with-preamble/output.map
@@ -0,0 +1,15 @@
+{
+  "mappings": ";AAAA,SAASA,MACLC,QAAQC,GAAG,CAAC,MAChB,CAEAF",
+  "names": [
+    "foo",
+    "console",
+    "log"
+  ],
+  "sources": [
+    "$DIR/tests/minify/issue-7475/1-with-preamble/input.js"
+  ],
+  "sourcesContent": [
+    "function foo() {\n    console.log('Foo')\n}\n\nfoo()"
+  ],
+  "version": 3
+}
diff --git a/crates/swc/tests/minify/issue-7475/2-no-preamble/config.json b/crates/swc/tests/minify/issue-7475/2-no-preamble/config.json
@@ -0,0 +1,3 @@
+{
+    "format": {}
+}
diff --git a/crates/swc/tests/minify/issue-7475/2-no-preamble/input.js b/crates/swc/tests/minify/issue-7475/2-no-preamble/input.js
@@ -0,0 +1,5 @@
+function foo() {
+    console.log('Foo')
+}
+
+foo()
diff --git a/crates/swc/tests/minify/issue-7475/2-no-preamble/output.js b/crates/swc/tests/minify/issue-7475/2-no-preamble/output.js
@@ -0,0 +1 @@
+function foo(){console.log("Foo")}foo();
diff --git a/crates/swc/tests/minify/issue-7475/2-no-preamble/output.map b/crates/swc/tests/minify/issue-7475/2-no-preamble/output.map
@@ -0,0 +1,15 @@
+{
+  "mappings": "AAAA,SAASA,MACLC,QAAQC,GAAG,CAAC,MAChB,CAEAF",
+  "names": [
+    "foo",
+    "console",
+    "log"
+  ],
+  "sources": [
+    "$DIR/tests/minify/issue-7475/2-no-preamble/input.js"
+  ],
+  "sourcesContent": [
+    "function foo() {\n    console.log('Foo')\n}\n\nfoo()"
+  ],
+  "version": 3
+}
diff --git a/crates/swc/tests/projects.rs b/crates/swc/tests/projects.rs
@@ -769,6 +769,7 @@ fn should_visit() {
                 Some(&comments),
                 config.emit_source_map_columns,
                 false,
+                Default::default(),
             )
             .unwrap()
             .code)
@@ -1130,3 +1131,36 @@ fn issue_7513_2() {
     println!("{}", output.code);
     assert_eq!(output.code, "const a={ignoreBOM:!0,fatal:!0};");
 }
+
+#[testing::fixture("tests/minify/**/input.js")]
+fn minify(input_js: PathBuf) {
+    let input_dir = input_js.parent().unwrap();
+    let config_json_path = input_dir.join("config.json");
+
+    testing::run_test2(false, |cm, handler| {
+        let c = Compiler::new(cm);
+        let fm = c.cm.load_file(&input_js).unwrap();
+
+        let mut config: JsMinifyOptions =
+            serde_json::from_str(&std::fs::read_to_string(&config_json_path).unwrap()).unwrap();
+
+        config.source_map = BoolOrDataConfig::from_bool(true);
+        let output = c.minify(fm, &handler, &config).unwrap();
+
+        NormalizedOutput::from(output.code)
+            .compare_to_file(input_dir.join("output.js"))
+            .unwrap();
+
+        let map = output.map.map(|json| {
+            let json: serde_json::Value = serde_json::from_str(&json).unwrap();
+            serde_json::to_string_pretty(&json).unwrap()
+        });
+
+        NormalizedOutput::from(map.unwrap())
+            .compare_to_file(input_dir.join("output.map"))
+            .unwrap();
+
+        Ok(())
+    })
+    .unwrap()
+}
diff --git a/crates/swc_ecma_codegen/src/text_writer/basic_impl.rs b/crates/swc_ecma_codegen/src/text_writer/basic_impl.rs
@@ -46,6 +46,13 @@ impl<'a, W: Write> JsWriter<'a, W> {
         }
     }
 
+    pub fn preamble(&mut self, s: &str) -> Result {
+        self.raw_write(s)?;
+        self.update_pos(s);
+
+        Ok(())
+    }
+
     /// Sets the indentation string. Defaults to four spaces.
     pub fn set_indent_str(&mut self, indent_str: &'static str) {
         self.indent_str = indent_str;

diff --git a/crates/swc_node_bundler/tests/fixture.rs b/crates/swc_node_bundler/tests/fixture.rs
@@ -99,6 +99,7 @@ fn pass(input_dir: PathBuf) {
                             Some(&comments),
                             false,
                             false,
+                            Default::default(),
                         )
                         .expect("failed to print?")
                         .code;
Benchmark suite	Current: `6e5d8b3`	Previous: `1d9f972`	Ratio
`es/full/bugs-1`	`374417` ns/iter (`± 12906`)	`316290` ns/iter (`± 7873`)	`1.18`
`es/full/minify/libraries/antd`	`2146905995` ns/iter (`± 31022751`)	`1469987432` ns/iter (`± 5561398`)	`1.46`
`es/full/minify/libraries/d3`	`458019398` ns/iter (`± 20375984`)	`315728175` ns/iter (`± 4268394`)	`1.45`
`es/full/minify/libraries/echarts`	`1739869667` ns/iter (`± 46565211`)	`1184262386` ns/iter (`± 5559691`)	`1.47`
`es/full/minify/libraries/jquery`	`113149990` ns/iter (`± 1302806`)	`95027552` ns/iter (`± 260650`)	`1.19`
`es/full/minify/libraries/lodash`	`138005168` ns/iter (`± 1776251`)	`112756927` ns/iter (`± 333243`)	`1.22`
`es/full/minify/libraries/moment`	`69317021` ns/iter (`± 2911808`)	`55846668` ns/iter (`± 219419`)	`1.24`
`es/full/minify/libraries/react`	`24207797` ns/iter (`± 650982`)	`20018235` ns/iter (`± 67261`)	`1.21`
`es/full/minify/libraries/terser`	`334742032` ns/iter (`± 9697064`)	`244634825` ns/iter (`± 642604`)	`1.37`
`es/full/minify/libraries/three`	`593107006` ns/iter (`± 10659853`)	`432561203` ns/iter (`± 882985`)	`1.37`
`es/full/minify/libraries/typescript`	`4314130384` ns/iter (`± 129987928`)	`2995232414` ns/iter (`± 9159317`)	`1.44`
`es/full/minify/libraries/victory`	`898601471` ns/iter (`± 20412538`)	`629338607` ns/iter (`± 14512555`)	`1.43`
`es/full/minify/libraries/vue`	`167290559` ns/iter (`± 2674260`)	`135562637` ns/iter (`± 202674`)	`1.23`
`es/full/codegen/es3`	`41810` ns/iter (`± 82`)	`35929` ns/iter (`± 107`)	`1.16`
`es/full/codegen/es5`	`41849` ns/iter (`± 108`)	`36139` ns/iter (`± 130`)	`1.16`
`es/full/codegen/es2015`	`41933` ns/iter (`± 81`)	`36064` ns/iter (`± 85`)	`1.16`
`es/full/codegen/es2016`	`41915` ns/iter (`± 115`)	`36017` ns/iter (`± 99`)	`1.16`
`es/full/codegen/es2017`	`41931` ns/iter (`± 66`)	`35977` ns/iter (`± 90`)	`1.17`
`es/full/codegen/es2018`	`41917` ns/iter (`± 70`)	`36003` ns/iter (`± 68`)	`1.16`
`es/full/codegen/es2019`	`41841` ns/iter (`± 67`)	`36055` ns/iter (`± 67`)	`1.16`
`es/full/codegen/es2020`	`41875` ns/iter (`± 111`)	`36188` ns/iter (`± 113`)	`1.16`
`es/full/all/es3`	`210522788` ns/iter (`± 3692829`)	`179703631` ns/iter (`± 863706`)	`1.17`
`es/full/all/es5`	`201533904` ns/iter (`± 3755300`)	`169668890` ns/iter (`± 380717`)	`1.19`
`es/full/all/es2015`	`158910523` ns/iter (`± 2363631`)	`126468094` ns/iter (`± 332183`)	`1.26`
`es/full/all/es2016`	`158281789` ns/iter (`± 1846758`)	`125170792` ns/iter (`± 424045`)	`1.26`
`es/full/all/es2017`	`156764246` ns/iter (`± 2119447`)	`124393777` ns/iter (`± 598085`)	`1.26`
`es/full/all/es2018`	`153186677` ns/iter (`± 1531012`)	`122314795` ns/iter (`± 536454`)	`1.25`
`es/full/all/es2019`	`152916457` ns/iter (`± 1781199`)	`122284908` ns/iter (`± 654134`)	`1.25`
`es/full/all/es2020`	`151964315` ns/iter (`± 3060253`)	`117511627` ns/iter (`± 664901`)	`1.29`
`es/full/parser`	`620177` ns/iter (`± 14854`)	`508551` ns/iter (`± 5346`)	`1.22`
`es/full/base/fixer`	`24688` ns/iter (`± 49`)	`18926` ns/iter (`± 190`)	`1.30`
`es/full/base/resolver_and_hygiene`	`105167` ns/iter (`± 179`)	`91989` ns/iter (`± 296`)	`1.14`
`serialization of serde`	`257` ns/iter (`± 0`)	`295` ns/iter (`± 0`)	`0.87`
`css/minify/libraries/bootstrap`	`39660822` ns/iter (`± 596261`)	`31125476` ns/iter (`± 57045`)	`1.27`
`css/visitor/compare/clone`	`2371276` ns/iter (`± 10621`)	`1960866` ns/iter (`± 24862`)	`1.21`
`css/visitor/compare/visit_mut_span`	`2554937` ns/iter (`± 5424`)	`2061138` ns/iter (`± 10418`)	`1.24`
`css/visitor/compare/visit_mut_span_panic`	`2649818` ns/iter (`± 7273`)	`2121527` ns/iter (`± 11386`)	`1.25`
`css/visitor/compare/fold_span`	`3385218` ns/iter (`± 63592`)	`2843244` ns/iter (`± 14802`)	`1.19`
`css/visitor/compare/fold_span_panic`	`3571571` ns/iter (`± 69680`)	`3069907` ns/iter (`± 11526`)	`1.16`
`css/lexer/bootstrap_5_1_3`	`5593730` ns/iter (`± 3696`)	`5015191` ns/iter (`± 6865`)	`1.12`
`css/lexer/foundation_6_7_4`	`4708198` ns/iter (`± 3240`)	`4017363` ns/iter (`± 2923`)	`1.17`
`css/lexer/tailwind_3_1_1`	`892693` ns/iter (`± 736`)	`982296` ns/iter (`± 738`)	`0.91`
`css/parser/bootstrap_5_1_3`	`23941891` ns/iter (`± 112974`)	`20327362` ns/iter (`± 47147`)	`1.18`
`css/parser/foundation_6_7_4`	`19942380` ns/iter (`± 85664`)	`16385733` ns/iter (`± 14844`)	`1.22`
`css/parser/tailwind_3_1_1`	`3670059` ns/iter (`± 2238`)	`3172898` ns/iter (`± 4131`)	`1.16`
`es/codegen/colors`	`743415` ns/iter (`± 403312`)	`736637` ns/iter (`± 400810`)	`1.01`
`es/codegen/large`	`3101716` ns/iter (`± 1620078`)	`2968763` ns/iter (`± 1550391`)	`1.04`
`es/codegen/with-parser/colors`	`58368` ns/iter (`± 549`)	`49552` ns/iter (`± 170`)	`1.18`
`es/codegen/with-parser/large`	`590936` ns/iter (`± 1858`)	`531070` ns/iter (`± 1455`)	`1.11`
`es/minify/libraries/antd`	`2061689699` ns/iter (`± 30234949`)	`1296957002` ns/iter (`± 13830003`)	`1.59`
`es/minify/libraries/d3`	`348613192` ns/iter (`± 6058495`)	`278561816` ns/iter (`± 290913`)	`1.25`
`es/minify/libraries/echarts`	`1423076238` ns/iter (`± 17994345`)	`1022901087` ns/iter (`± 3251581`)	`1.39`
`es/minify/libraries/jquery`	`104459522` ns/iter (`± 3073439`)	`83801823` ns/iter (`± 127013`)	`1.25`
`es/minify/libraries/lodash`	`129971220` ns/iter (`± 1495999`)	`102693525` ns/iter (`± 180973`)	`1.27`
`es/minify/libraries/moment`	`59174156` ns/iter (`± 1346518`)	`49544610` ns/iter (`± 85585`)	`1.19`
`es/minify/libraries/react`	`20800080` ns/iter (`± 138286`)	`18045415` ns/iter (`± 66305`)	`1.15`
`es/minify/libraries/terser`	`269877796` ns/iter (`± 5410273`)	`212199799` ns/iter (`± 368110`)	`1.27`
`es/minify/libraries/three`	`537214239` ns/iter (`± 47881948`)	`364799698` ns/iter (`± 905205`)	`1.47`
`es/minify/libraries/typescript`	`3647340241` ns/iter (`± 76130108`)	`2556049742` ns/iter (`± 8447709`)	`1.43`
`es/minify/libraries/victory`	`773407934` ns/iter (`± 45070154`)	`532700473` ns/iter (`± 2115023`)	`1.45`
`es/minify/libraries/vue`	`159608280` ns/iter (`± 3360406`)	`124102630` ns/iter (`± 223481`)	`1.29`
`es/visitor/compare/clone`	`2449361` ns/iter (`± 25533`)	`2072388` ns/iter (`± 6405`)	`1.18`
`es/visitor/compare/visit_mut_span`	`2781676` ns/iter (`± 25717`)	`2399229` ns/iter (`± 4282`)	`1.16`
`es/visitor/compare/visit_mut_span_panic`	`2840230` ns/iter (`± 4128`)	`2438632` ns/iter (`± 3866`)	`1.16`
`es/visitor/compare/fold_span`	`3968927` ns/iter (`± 53739`)	`3478431` ns/iter (`± 4147`)	`1.14`
`es/visitor/compare/fold_span_panic`	`4126013` ns/iter (`± 125989`)	`3617450` ns/iter (`± 6555`)	`1.14`
`es/lexer/colors`	`14577` ns/iter (`± 22`)	`13117` ns/iter (`± 1119`)	`1.11`
`es/lexer/angular`	`6955523` ns/iter (`± 12401`)	`6282318` ns/iter (`± 16834`)	`1.11`
`es/lexer/backbone`	`847173` ns/iter (`± 320`)	`806559` ns/iter (`± 2636`)	`1.05`
`es/lexer/jquery`	`4772851` ns/iter (`± 3689`)	`4557972` ns/iter (`± 2941`)	`1.05`
`es/lexer/jquery mobile`	`7363627` ns/iter (`± 32240`)	`6976123` ns/iter (`± 3022`)	`1.06`
`es/lexer/mootools`	`3744768` ns/iter (`± 1638`)	`3591239` ns/iter (`± 3204`)	`1.04`
`es/lexer/underscore`	`704026` ns/iter (`± 855`)	`669738` ns/iter (`± 2144`)	`1.05`
`es/lexer/three`	`22359801` ns/iter (`± 26796`)	`21262699` ns/iter (`± 27333`)	`1.05`
`es/lexer/yui`	`4287515` ns/iter (`± 2146`)	`4070744` ns/iter (`± 1337`)	`1.05`
`es/parser/colors`	`33526` ns/iter (`± 71`)	`29110` ns/iter (`± 61`)	`1.15`
`es/parser/angular`	`18876960` ns/iter (`± 358123`)	`14440785` ns/iter (`± 72100`)	`1.31`
`es/parser/backbone`	`2449653` ns/iter (`± 8616`)	`2150646` ns/iter (`± 7112`)	`1.14`
`es/parser/jquery`	`13480904` ns/iter (`± 74062`)	`11689291` ns/iter (`± 37814`)	`1.15`
`es/parser/jquery mobile`	`20838603` ns/iter (`± 299020`)	`17788967` ns/iter (`± 45948`)	`1.17`
`es/parser/mootools`	`10106795` ns/iter (`± 27328`)	`8973169` ns/iter (`± 13389`)	`1.13`
`es/parser/underscore`	`2105748` ns/iter (`± 15834`)	`1864676` ns/iter (`± 8983`)	`1.13`
`es/parser/three`	`66869975` ns/iter (`± 303585`)	`49518983` ns/iter (`± 73570`)	`1.35`
`es/parser/yui`	`10469749` ns/iter (`± 117113`)	`9009570` ns/iter (`± 29756`)	`1.16`
`es/preset-env/usage/builtin_type`	`152703` ns/iter (`± 33562`)	`145916` ns/iter (`± 32999`)	`1.05`
`es/preset-env/usage/property`	`29719` ns/iter (`± 116`)	`19478` ns/iter (`± 54`)	`1.53`
`es/resolver/typescript`	`152544662` ns/iter (`± 5236321`)	`93717358` ns/iter (`± 463320`)	`1.63`
`es/fixer/typescript`	`109010309` ns/iter (`± 1395956`)	`64712810` ns/iter (`± 419432`)	`1.68`
`es/hygiene/typescript`	`243684196` ns/iter (`± 4302475`)	`141398187` ns/iter (`± 540594`)	`1.72`
`es/resolver_with_hygiene/typescript`	`484889339` ns/iter (`± 7292606`)	`302258554` ns/iter (`± 1542444`)	`1.60`
`es/visitor/base-perf/module_clone`	`85429` ns/iter (`± 550`)	`61358` ns/iter (`± 198`)	`1.39`
`es/visitor/base-perf/fold_empty`	`94569` ns/iter (`± 409`)	`65007` ns/iter (`± 252`)	`1.45`
`es/visitor/base-perf/fold_noop_impl_all`	`94721` ns/iter (`± 316`)	`65212` ns/iter (`± 327`)	`1.45`
`es/visitor/base-perf/fold_noop_impl_vec`	`95063` ns/iter (`± 354`)	`65307` ns/iter (`± 195`)	`1.46`
`es/visitor/base-perf/boxing_boxed_clone`	`60` ns/iter (`± 0`)	`56` ns/iter (`± 0`)	`1.07`
`es/visitor/base-perf/boxing_unboxed_clone`	`44` ns/iter (`± 0`)	`41` ns/iter (`± 0`)	`1.07`
`es/visitor/base-perf/boxing_boxed`	`110` ns/iter (`± 0`)	`108` ns/iter (`± 0`)	`1.02`
`es/visitor/base-perf/boxing_unboxed`	`82` ns/iter (`± 0`)	`77` ns/iter (`± 0`)	`1.06`
`es/visitor/base-perf/visit_contains_this`	`3545` ns/iter (`± 85`)	`2608` ns/iter (`± 10`)	`1.36`
`es/base/parallel/resolver/typescript`	`7703272047` ns/iter (`± 560278471`)	`4298308214` ns/iter (`± 295157183`)	`1.79`
`es/base/parallel/hygiene/typescript`	`2858919350` ns/iter (`± 42135501`)	`1585120820` ns/iter (`± 11653946`)	`1.80`
`misc/visitors/time-complexity/time 5`	`104` ns/iter (`± 0`)	`109` ns/iter (`± 0`)	`0.95`
`misc/visitors/time-complexity/time 10`	`339` ns/iter (`± 3`)	`268` ns/iter (`± 0`)	`1.26`
`misc/visitors/time-complexity/time 15`	`631` ns/iter (`± 12`)	`519` ns/iter (`± 7`)	`1.22`
`misc/visitors/time-complexity/time 20`	`1169` ns/iter (`± 33`)	`931` ns/iter (`± 2`)	`1.26`
`misc/visitors/time-complexity/time 40`	`6020` ns/iter (`± 3`)	`3783` ns/iter (`± 12`)	`1.59`
`misc/visitors/time-complexity/time 60`	`15392` ns/iter (`± 78`)	`7829` ns/iter (`± 33`)	`1.97`
`es/full-target/es2016`	`270985` ns/iter (`± 396`)	`240215` ns/iter (`± 672`)	`1.13`
`es/full-target/es2017`	`261207` ns/iter (`± 491`)	`224149` ns/iter (`± 652`)	`1.17`
`es/full-target/es2018`	`250335` ns/iter (`± 452`)	`214309` ns/iter (`± 836`)	`1.17`
`es2020_nullish_coalescing`	`97666` ns/iter (`± 547`)	`71181` ns/iter (`± 436`)	`1.37`
`es2020_optional_chaining`	`115342` ns/iter (`± 380`)	`83871` ns/iter (`± 173`)	`1.38`
`es2022_class_properties`	`156589` ns/iter (`± 397`)	`121512` ns/iter (`± 427`)	`1.29`
`es2018_object_rest_spread`	`100085` ns/iter (`± 325`)	`76421` ns/iter (`± 172`)	`1.31`
`es2019_optional_catch_binding`	`88659` ns/iter (`± 232`)	`64142` ns/iter (`± 165`)	`1.38`
`es2017_async_to_generator`	`89094` ns/iter (`± 246`)	`64772` ns/iter (`± 232`)	`1.38`
`es2016_exponentiation`	`95958` ns/iter (`± 271`)	`70498` ns/iter (`± 155`)	`1.36`
`es2015_arrow`	`98985` ns/iter (`± 206`)	`72887` ns/iter (`± 169`)	`1.36`
`es2015_block_scoped_fn`	`96759` ns/iter (`± 237`)	`69416` ns/iter (`± 154`)	`1.39`
`es2015_block_scoping`	`184000` ns/iter (`± 498`)	`131831` ns/iter (`± 473`)	`1.40`