feat(es/minifier): Skip function declarations in sequential inliner (#…

…6147)

crates/swc/tests/tsc-references/genericCallWithObjectTypeArgsAndConstraints5.2.minified.js

@@ -1,10 +1,9 @@
 //// [genericCallWithObjectTypeArgsAndConstraints5.ts]
-var c, d;
 function foo(t, t2) {
     return function(x) {
         return t2;
     };
 }
-foo(d, c), foo(function() {
+foo(void 0, void 0), foo(function() {
     return 1;
 }, function() {});

crates/swc/tests/tsc-references/tsxStatelessFunctionComponentOverload5.2.minified.js

@@ -13,14 +13,14 @@ define([
         get: function() {
             return MainButton;
         }
-    }), _extends = _extends.default;
+    });
     var obj3, obj0 = {
         to: "world"
     };
     function MainButton(props) {
         return props.to ? this._buildMainLink(props) : this._buildMainButton(props);
     }
-    _extends({
+    (_extends = _extends.default)({
         onClick: function(e) {}
     }, obj0), _extends({}, {
         to: "10000"

crates/swc/tests/tsc-references/tsxStatelessFunctionComponentOverload6.2.minified.js

@@ -13,15 +13,15 @@ define([
         get: function() {
             return MainButton;
         }
-    }), _extends = _extends.default;
+    });
     var obj1, obj = {
         children: "hi",
         to: "boo"
     };
     function MainButton(props) {
         return props.to ? this._buildMainLink(props) : this._buildMainButton(props);
     }
-    _extends({}, obj), _extends({}, {
+    (_extends = _extends.default)({}, obj), _extends({}, {
         to: 10000
     }, obj), _extends({}, obj1), _extends({}, obj1, {
         to: "/to/somewhere"

crates/swc_ecma_minifier/src/compress/optimize/sequences.rs

@@ -591,6 +591,26 @@ where
                 vec![Mergable::Expr(&mut s.arg)]
             }
 
+            Stmt::Decl(Decl::Fn(f)) => {
+                // Check for side effects
+
+                if !f.function.decorators.is_empty() {
+                    return None;
+                }
+                for p in &f.function.params {
+                    if !p.decorators.is_empty() {
+                        return None;
+                    }
+
+                    if !self.is_pat_skippable_for_seq(None, &p.pat) {
+                        return None;
+                    }
+                }
+
+                // Side-effect free function can be skipped.
+                vec![]
+            }
+
             _ => return None,
         })
     }
@@ -948,6 +968,57 @@ where
         Ok(())
     }
 
+    fn is_pat_skippable_for_seq(&mut self, a: Option<&Mergable>, p: &Pat) -> bool {
+        match p {
+            Pat::Ident(_) => true,
+            Pat::Invalid(_) => false,
+
+            Pat::Array(p) => {
+                for elem in p.elems.iter().flatten() {
+                    if !self.is_pat_skippable_for_seq(a, elem) {
+                        return false;
+                    }
+                }
+
+                true
+            }
+            Pat::Rest(p) => {
+                if !self.is_pat_skippable_for_seq(a, &p.arg) {
+                    return false;
+                }
+
+                true
+            }
+            Pat::Object(p) => {
+                for prop in &p.props {
+                    match prop {
+                        ObjectPatProp::KeyValue(KeyValuePatProp { value, key, .. }) => {
+                            if let PropName::Computed(key) = key {
+                                if !self.is_skippable_for_seq(a, &key.expr) {
+                                    return false;
+                                }
+                            }
+
+                            if !self.is_pat_skippable_for_seq(a, value) {
+                                return false;
+                            }
+                        }
+                        ObjectPatProp::Assign(AssignPatProp { .. }) => return false,
+                        ObjectPatProp::Rest(RestPat { arg, .. }) => {
+                            if !self.is_pat_skippable_for_seq(a, arg) {
+                                return false;
+                            }
+                        }
+                    }
+                }
+
+                true
+            }
+            Pat::Assign(..) => false,
+            Pat::Expr(e) => self.is_skippable_for_seq(a, e),
+        }
+    }
+
     #[cfg_attr(feature = "debug", tracing::instrument(skip_all))]
     fn is_skippable_for_seq(&self, a: Option<&Mergable>, e: &Expr) -> bool {
         if self.ctx.in_try_block {

crates/swc_ecma_minifier/tests/benches-full/echarts.js

@@ -35410,12 +35410,6 @@
         'OTransform',
         'MozTransform',
         'msTransform'
-    ]), TRANSITION_VENDOR = testStyle([
-        'webkitTransition',
-        'transition',
-        'OTransition',
-        'MozTransition',
-        'msTransition'
     ]);
     function toCSSVendorPrefix(styleVendor, styleProp) {
         if (!styleVendor) return styleProp;
@@ -35427,7 +35421,13 @@
         var stl = el.currentStyle || document.defaultView && document.defaultView.getComputedStyle(el);
         return stl ? style ? stl[style] : stl : null;
     }
-    var CSS_TRANSITION_VENDOR = toCSSVendorPrefix(TRANSITION_VENDOR, 'transition'), CSS_TRANSFORM_VENDOR = toCSSVendorPrefix(TRANSFORM_VENDOR, 'transform'), gCssText = "position:absolute;display:block;border-style:solid;white-space:nowrap;z-index:9999999;" + (env1.transform3dSupported ? 'will-change:transform;' : '');
+    var CSS_TRANSITION_VENDOR = toCSSVendorPrefix(testStyle([
+        'webkitTransition',
+        'transition',
+        'OTransition',
+        'MozTransition',
+        'msTransition'
+    ]), 'transition'), CSS_TRANSFORM_VENDOR = toCSSVendorPrefix(TRANSFORM_VENDOR, 'transform'), gCssText = "position:absolute;display:block;border-style:solid;white-space:nowrap;z-index:9999999;" + (env1.transform3dSupported ? 'will-change:transform;' : '');
     function assembleTransform(x, y, toString) {
         var x0 = x.toFixed(0) + 'px', y0 = y.toFixed(0) + 'px';
         if (!env1.transformSupported) return toString ? "top:" + y0 + ";left:" + x0 + ";" : [

crates/swc_ecma_minifier/tests/benches-full/terser.js

@@ -4321,9 +4321,6 @@
         function next_indent() {
             return indentation + options.indent_level;
         }
-        var add_mapping = mappings ? function(token, name) {
-            mapping_token = token, mapping_name = name;
-        } : noop;
         function get() {
             return might_add_newline && ensure_line_len(), OUTPUT.toString();
         }
@@ -4408,7 +4405,9 @@
                 var ret = cont();
                 return print("]"), ret;
             },
-            add_mapping: add_mapping,
+            add_mapping: mappings ? function(token, name) {
+                mapping_token = token, mapping_name = name;
+            } : noop,
             option: function(opt) {
                 return options[opt];
             },

crates/swc_ecma_minifier/tests/fixture/issues/2257/full/output.js

@@ -1952,12 +1952,12 @@
         },
         11864: function(module, __unused_webpack_exports, __webpack_require__) {
             "use strict";
-            var utils = __webpack_require__(99677), bind = __webpack_require__(81470), Axios = __webpack_require__(250), mergeConfig = __webpack_require__(10882), defaults = __webpack_require__(52275);
+            var utils = __webpack_require__(99677), bind = __webpack_require__(81470), Axios = __webpack_require__(250), mergeConfig = __webpack_require__(10882);
             function createInstance(defaultConfig) {
                 var context = new Axios(defaultConfig), instance = bind(Axios.prototype.request, context);
                 return utils.extend(instance, Axios.prototype, context), utils.extend(instance, context), instance;
             }
-            var axios = createInstance(defaults);
+            var axios = createInstance(__webpack_require__(52275));
             axios.Axios = Axios, axios.create = function(instanceConfig) {
                 return createInstance(mergeConfig(axios.defaults, instanceConfig));
             }, axios.Cancel = __webpack_require__(69651), axios.CancelToken = __webpack_require__(88149), axios.isCancel = __webpack_require__(37606), axios.all = function(promises) {

crates/swc_ecma_minifier/tests/fixture/next/wrap-contracts/output.js

@@ -5972,14 +5972,14 @@
         },
         1609: function(module, __unused_webpack_exports, __webpack_require__) {
             "use strict";
-            var utils = __webpack_require__(4867), bind = __webpack_require__(1849), Axios = __webpack_require__(321), mergeConfig = __webpack_require__(7185), defaults = __webpack_require__(5546);
+            var utils = __webpack_require__(4867), bind = __webpack_require__(1849), Axios = __webpack_require__(321), mergeConfig = __webpack_require__(7185);
             function createInstance(defaultConfig) {
                 var context = new Axios(defaultConfig), instance = bind(Axios.prototype.request, context);
                 return utils.extend(instance, Axios.prototype, context), utils.extend(instance, context), instance.create = function(instanceConfig) {
                     return createInstance(mergeConfig(defaultConfig, instanceConfig));
                 }, instance;
             }
-            var axios = createInstance(defaults);
+            var axios = createInstance(__webpack_require__(5546));
             axios.Axios = Axios, axios.CanceledError = __webpack_require__(644), axios.CancelToken = __webpack_require__(4972), axios.isCancel = __webpack_require__(6502), axios.VERSION = __webpack_require__(7288).version, axios.toFormData = __webpack_require__(7675), axios.AxiosError = __webpack_require__(723), axios.Cancel = axios.CanceledError, axios.all = function(promises) {
                 return Promise.all(promises);
             }, axios.spread = __webpack_require__(8713), axios.isAxiosError = __webpack_require__(6268), module.exports = axios, module.exports.default = axios;
@@ -6037,11 +6037,11 @@
         },
         644: function(module, __unused_webpack_exports, __webpack_require__) {
             "use strict";
-            var AxiosError = __webpack_require__(723), utils = __webpack_require__(4867);
+            var AxiosError = __webpack_require__(723);
             function CanceledError(message) {
                 AxiosError.call(this, null == message ? 'canceled' : message, AxiosError.ERR_CANCELED), this.name = 'CanceledError';
             }
-            utils.inherits(CanceledError, AxiosError, {
+            __webpack_require__(4867).inherits(CanceledError, AxiosError, {
                 __CANCEL__: !0
             }), module.exports = CanceledError;
         },

crates/swc_ecma_minifier/tests/pass-1/seq/1/output.js

@@ -89,4 +89,4 @@ function unix() {
 function toDate() {
     return new Date(this.valueOf());
 }
-console.log(MS_PER_400_YEARS);
+console.log(3506328 * (60 * (60 * 1000)));

crates/swc_ecma_minifier/tests/projects/output/jquery.mobile-1.4.2.js

@@ -1053,11 +1053,11 @@
         }), $.event.special.scrollstart = {
             enabled: !0,
             setup: function() {
-                var scrolling, timer, thisObject = this, $this = $(thisObject);
+                var scrolling, timer, thisObject = this;
                 function trigger(event1, state) {
                     triggerCustomEvent(thisObject, (scrolling = state) ? "scrollstart" : "scrollstop", event1);
                 }
-                $this.bind(scrollEvent, function(event1) {
+                $(thisObject).bind(scrollEvent, function(event1) {
                     $.event.special.scrollstart.enabled && (scrolling || trigger(event1, !0), clearTimeout(timer), timer = setTimeout(function() {
                         trigger(event1, !1);
                     }, 50));