feat(es/minifeir): Inline lazily initialized literals (#10752)

**Related issue:**

 - Closes #10746

Author: kdy1

crates/swc_ecma_minifier/scripts/test.sh

@@ -8,7 +8,7 @@ export SWC_RUN=0
 
 touch tests/compress.rs
 
-UPDATE=1 cargo test -p swc_ecma_minifier -p swc --test size
+RUST_LOG=off UPDATE=1 cargo test -p swc_ecma_minifier -p swc --test size
 cargo test -p swc_ecma_minifier -p swc --no-fail-fast --test projects --test tsc --test compress --test mangle --features concurrent $@
 
 # find ../swc/tests/ -type f -empty -delete

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

@@ -259,7 +259,14 @@ impl Optimizer<'_> {
 
                     Expr::Lit(lit) => match lit {
                         Lit::Str(s) => {
-                            if ref_count == 1 || s.value.len() <= 3 {
+                            // If the string literal is declared without initializer and assigned
+                            // once, we can inline it.
+                            if (ref_count == 1
+                                || (ref_count == 2
+                                    && usage.assign_count == 1
+                                    && usage.flags.intersects(VarUsageInfoFlags::LAZY_INIT)))
+                                || s.value.len() <= 3
+                            {
                                 true
                             } else {
                                 self.vars

crates/swc_ecma_minifier/src/program_data.rs

@@ -88,6 +88,8 @@ bitflags::bitflags! {
         /// `a` in `foo(<a />)`
         const USED_AS_JSX_CALLEE       = 1 << 24;
 
+        /// The variable is declared without initializer.
+        const LAZY_INIT                 = 1 << 25;
     }
 
     #[derive(Debug, Default, Clone, Copy)]
@@ -581,6 +583,10 @@ impl VarDataLike for VarUsageInfo {
         self.flags.insert(VarUsageInfoFlags::DECLARED_AS_FN_PARAM);
     }
 
+    fn mark_as_lazy_init(&mut self) {
+        self.flags.insert(VarUsageInfoFlags::LAZY_INIT);
+    }
+
     fn mark_declared_as_fn_decl(&mut self) {
         self.flags.insert(VarUsageInfoFlags::DECLARED_AS_FN_DECL);
     }

crates/swc_ecma_minifier/src/util/mod.rs

@@ -29,6 +29,8 @@ pub trait ModuleItemExt:
 {
     fn as_module_decl(&self) -> Result<&ModuleDecl, &Stmt>;
 
+    fn as_module_decl_mut(&mut self) -> Result<&mut ModuleDecl, &mut Stmt>;
+
     fn from_module_item(item: ModuleItem) -> Self;
 
     fn into_module_item(self) -> ModuleItem {
@@ -46,6 +48,10 @@ impl ModuleItemExt for Stmt {
         Err(self)
     }
 
+    fn as_module_decl_mut(&mut self) -> Result<&mut ModuleDecl, &mut Stmt> {
+        Err(self)
+    }
+
     fn from_module_item(item: ModuleItem) -> Self {
         item.expect_stmt()
     }
@@ -63,6 +69,13 @@ impl ModuleItemExt for ModuleItem {
         }
     }
 
+    fn as_module_decl_mut(&mut self) -> Result<&mut ModuleDecl, &mut Stmt> {
+        match self {
+            ModuleItem::ModuleDecl(v) => Ok(v),
+            ModuleItem::Stmt(v) => Err(v),
+        }
+    }
+
     fn from_module_item(item: ModuleItem) -> Self {
         item
     }

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

@@ -34,7 +34,7 @@
     LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
     OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
     PERFORMANCE OF THIS SOFTWARE.
-    ***************************************************************************** */ /* global Reflect, Promise */ var ua, browser, firefox, ie, edge, weChat, style, mouseHandlerNames, pointerEventNameMap, pointerHandlerNames, classAttr, subTypeDefaulters, _super, mainType, creator, _ctx, _cachedFont, requestAnimationFrame, reCreateSeriesIndices, assertSeriesInitialized, initBase, _a, _b, _c, providerMethods, mountMethods, seriesType, nodeParsers, prepare, prepareView, updateDirectly, updateMethods, doConvertPixel, updateStreamModes, doDispatchAction, flushPendingActions, triggerUpdatedEvent, bindRenderedEvent, bindMouseEvent, clearColorPalette, render, renderComponents, renderSeries, performPostUpdateFuncs, createExtensionAPI, enableConnect, setTransitionOpt, markStatusToUpdate, applyChangedStates, defaultDimValueGetters, prepareInvertedIndex, getIndicesCtor, prepareStorage, getRawIndexWithoutIndices, getRawIndexWithIndices, getId, getIdNameFromStore, makeIdFromName, normalizeDimensions, validateDimensions, cloneListForMapAndSample, getInitialExtent, setItemDataAndSeriesIndex, transferProperties, checkNonStyleTansitionRefer, checkTransformPropRefer, extendStatics = function(d, b) {
+    ***************************************************************************** */ /* global Reflect, Promise */ var ua, browser, firefox, ie, edge, weChat, style, mouseHandlerNames, pointerEventNameMap, pointerHandlerNames, classAttr, subTypeDefaulters, _super, creator, _ctx, _cachedFont, requestAnimationFrame, reCreateSeriesIndices, assertSeriesInitialized, initBase, _a, _b, _c, providerMethods, mountMethods, seriesType, nodeParsers, prepare, prepareView, updateDirectly, updateMethods, doConvertPixel, updateStreamModes, doDispatchAction, flushPendingActions, triggerUpdatedEvent, bindRenderedEvent, bindMouseEvent, clearColorPalette, render, renderComponents, renderSeries, performPostUpdateFuncs, createExtensionAPI, enableConnect, setTransitionOpt, markStatusToUpdate, applyChangedStates, defaultDimValueGetters, prepareInvertedIndex, getIndicesCtor, prepareStorage, getRawIndexWithoutIndices, getRawIndexWithIndices, getId, getIdNameFromStore, makeIdFromName, normalizeDimensions, validateDimensions, cloneListForMapAndSample, getInitialExtent, setItemDataAndSeriesIndex, transferProperties, checkNonStyleTansitionRefer, checkTransformPropRefer, extendStatics = function(d, b) {
         return (extendStatics = Object.setPrototypeOf || ({
             __proto__: []
         }) instanceof Array && function(d, b) {
@@ -41507,7 +41507,7 @@
         }; // If both `xAxisIndex` `xAxisId` not set, it means 'all'.
         return null == setting.xAxisIndex && null == setting.xAxisId && (setting.xAxisIndex = 'all'), null == setting.yAxisIndex && null == setting.yAxisId && (setting.yAxisIndex = 'all'), setting;
     }
-    mainType = 'dataZoom', creator = function(ecModel) {
+    creator = function(ecModel) {
         var toolboxModel = ecModel.getComponent('toolbox', 0);
         if (toolboxModel) {
             var dzFeatureModel = toolboxModel.getModel([
@@ -41531,7 +41531,7 @@
             };
             newOpt[axisIndexPropName] = axisIndex, dzOptions.push(newOpt);
         }
-    }, assert(null == internalOptionCreatorMap.get(mainType) && creator), internalOptionCreatorMap.set(mainType, creator);
+    }, assert(null == internalOptionCreatorMap.get('dataZoom') && creator), internalOptionCreatorMap.set('dataZoom', creator);
     var TooltipModel = /** @class */ function(_super) {
         function TooltipModel() {
             var _this = null !== _super && _super.apply(this, arguments) || this;
@@ -41728,8 +41728,8 @@
         // this.hide();
         }, TooltipHTMLContent.prototype.show = function(tooltipModel, nearPointColor) {
             clearTimeout(this._hideTimeout), clearTimeout(this._longHideTimeout);
-            var enableTransition, onlyFade, cssText, transitionDuration, backgroundColor, shadowBlur, shadowColor, shadowOffsetX, shadowOffsetY, textStyleModel, padding, boxShadow, transitionCurve, transitionOption, transitionText, cssText1, fontSize, color, shadowColor1, shadowBlur1, shadowOffsetX1, shadowOffsetY1, el = this.el, style = el.style, styleCoord = this._styleCoord;
-            el.innerHTML ? style.cssText = gCssText + (enableTransition = !this._firstShow, onlyFade = this._longHide, cssText = [], transitionDuration = tooltipModel.get('transitionDuration'), backgroundColor = tooltipModel.get('backgroundColor'), shadowBlur = tooltipModel.get('shadowBlur'), shadowColor = tooltipModel.get('shadowColor'), shadowOffsetX = tooltipModel.get('shadowOffsetX'), shadowOffsetY = tooltipModel.get('shadowOffsetY'), textStyleModel = tooltipModel.getModel('textStyle'), padding = getPaddingFromTooltipModel(tooltipModel, 'html'), boxShadow = shadowOffsetX + "px " + shadowOffsetY + "px " + shadowBlur + "px " + shadowColor, cssText.push('box-shadow:' + boxShadow), enableTransition && transitionDuration && cssText.push((transitionText = "opacity" + (transitionOption = " " + transitionDuration / 2 + "s " + (transitionCurve = 'cubic-bezier(0.23,1,0.32,1)')) + ",visibility" + transitionOption, onlyFade || (transitionOption = " " + transitionDuration + "s " + transitionCurve, transitionText += env.transformSupported ? "," + TRANSFORM_VENDOR + transitionOption : ",left" + transitionOption + ",top" + transitionOption), CSS_TRANSITION_VENDOR + ':' + transitionText)), backgroundColor && (env.canvasSupported ? cssText.push('background-color:' + backgroundColor) : (// for ie
+            var enableTransition, onlyFade, cssText, transitionDuration, backgroundColor, shadowBlur, shadowColor, shadowOffsetX, shadowOffsetY, textStyleModel, padding, boxShadow, transitionOption, transitionText, cssText1, fontSize, color, shadowColor1, shadowBlur1, shadowOffsetX1, shadowOffsetY1, el = this.el, style = el.style, styleCoord = this._styleCoord;
+            el.innerHTML ? style.cssText = gCssText + (enableTransition = !this._firstShow, onlyFade = this._longHide, cssText = [], transitionDuration = tooltipModel.get('transitionDuration'), backgroundColor = tooltipModel.get('backgroundColor'), shadowBlur = tooltipModel.get('shadowBlur'), shadowColor = tooltipModel.get('shadowColor'), shadowOffsetX = tooltipModel.get('shadowOffsetX'), shadowOffsetY = tooltipModel.get('shadowOffsetY'), textStyleModel = tooltipModel.getModel('textStyle'), padding = getPaddingFromTooltipModel(tooltipModel, 'html'), boxShadow = shadowOffsetX + "px " + shadowOffsetY + "px " + shadowBlur + "px " + shadowColor, cssText.push('box-shadow:' + boxShadow), enableTransition && transitionDuration && cssText.push((transitionText = "opacity" + (transitionOption = " " + transitionDuration / 2 + "s cubic-bezier(0.23,1,0.32,1)") + ",visibility" + transitionOption, onlyFade || (transitionOption = " " + transitionDuration + "s cubic-bezier(0.23,1,0.32,1)", transitionText += env.transformSupported ? "," + TRANSFORM_VENDOR + transitionOption : ",left" + transitionOption + ",top" + transitionOption), CSS_TRANSITION_VENDOR + ':' + transitionText)), backgroundColor && (env.canvasSupported ? cssText.push('background-color:' + backgroundColor) : (// for ie
             cssText.push('background-color:#' + toHex(backgroundColor)), cssText.push('filter:alpha(opacity=70)'))), each([
                 'width',
                 'color',
@@ -45467,8 +45467,8 @@
         }, SliderZoomView.prototype.dispose = function() {
             this._clear(), _super.prototype.dispose.apply(this, arguments);
         }, SliderZoomView.prototype._clear = function() {
-            (fn = this[fnAttr = '_dispatchZoomAction']) && fn[ORIGIN_METHOD] && (this[fnAttr] = fn[ORIGIN_METHOD]);
-            var fnAttr, fn, zr = this.api.getZr();
+            (fn = this._dispatchZoomAction) && fn[ORIGIN_METHOD] && (this._dispatchZoomAction = fn[ORIGIN_METHOD]);
+            var fn, zr = this.api.getZr();
             zr.off('mousemove', this._onBrush), zr.off('mouseup', this._onBrushEnd);
         }, SliderZoomView.prototype._buildView = function() {
             var thisGroup = this.group;

crates/swc_ecma_minifier/tests/fixture/issues/10746/input.js

@@ -0,0 +1,9 @@
+const ErrorResponse = (statusCode, message) => {
+    return Response.json({
+        message
+    }, {
+        status: statusCode
+    });
+}
+
+export const unknownError = ErrorResponse(520, "Unknown error.");

crates/swc_ecma_minifier/tests/fixture/issues/10746/output.js

@@ -0,0 +1,5 @@
+export const unknownError = Response.json({
+    message: "Unknown error."
+}, {
+    status: 520
+});

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

@@ -17717,7 +17717,7 @@
         });
         // EXTERNAL MODULE: ./node_modules/_@babel_runtime@7.15.4@@babel/runtime/helpers/esm/inheritsLoose.js + 1 modules
         var inheritsLoose = __webpack_require__(48861), _react_17_0_2_react = __webpack_require__(59301), _prop_types_15_7_2_prop_types = __webpack_require__(68712), _prop_types_15_7_2_prop_types_default = /*#__PURE__*/ __webpack_require__.n(_prop_types_15_7_2_prop_types), esm_history = __webpack_require__(91520), commonjsGlobal = "undefined" != typeof globalThis ? globalThis : "undefined" != typeof window ? window : void 0 !== __webpack_require__.g ? __webpack_require__.g : {}, index = _react_17_0_2_react.createContext || function(defaultValue, calculateChangedBits) {
-            var key, _Provider$childContex, _Consumer$contextType, contextProp = "__create-react-context-" + (commonjsGlobal[key = "__global_unique_id__"] = (commonjsGlobal[key] || 0) + 1) + "__", Provider = /*#__PURE__*/ function(_Component) {
+            var _Provider$childContex, _Consumer$contextType, contextProp = "__create-react-context-" + (commonjsGlobal.__global_unique_id__ = (commonjsGlobal.__global_unique_id__ || 0) + 1) + "__", Provider = /*#__PURE__*/ function(_Component) {
                 function Provider() {
                     var _this, value, handlers;
                     return _this = _Component.apply(this, arguments) || this, value = _this.props.value, handlers = [], _this.emitter = {

crates/swc_ecma_minifier/tests/fixture/issues/emotion/react/1/output.js

@@ -344,7 +344,6 @@
                  * @param {number} length
                  * @return {string}
                  */ function prefix(value, length) {
-                                var search, search1;
                                 switch((((length << 2 ^ Utility_charat(value, 0)) << 2 ^ Utility_charat(value, 1)) << 2 ^ Utility_charat(value, 2)) << 2 ^ Utility_charat(value, 3)){
                                     // color-adjust
                                     case 5103:
@@ -454,7 +453,7 @@
                                                 return replace(value, /(.+:)(.+)-([^]+)/, "$1" + WEBKIT + "$2-$3$1" + MOZ + (108 == Utility_charat(value, length + 3) ? "$3" : "$2-$3")) + value;
                                             // (s)tretch
                                             case 115:
-                                                return ~(search = "stretch", value.indexOf(search)) ? prefix(replace(value, "stretch", "fill-available"), length) + value : value;
+                                                return ~value.indexOf("stretch") ? prefix(replace(value, "stretch", "fill-available"), length) + value : value;
                                         }
                                         break;
                                     // position: sticky
@@ -463,7 +462,7 @@
                                         if (115 !== Utility_charat(value, length + 1)) break;
                                     // display: (flex|inline-flex)
                                     case 6444:
-                                        switch(Utility_charat(value, Utility_strlen(value) - 3 - (~(search1 = "!important", value.indexOf(search1)) && 10))){
+                                        switch(Utility_charat(value, Utility_strlen(value) - 3 - (~value.indexOf("!important") && 10))){
                                             // stic(k)y
                                             case 107:
                                                 return replace(value, ":", ":" + WEBKIT) + value;

crates/swc_ecma_minifier/tests/fixture/next/syncfusion/933-e9f9a6bf671b96fc/output.js

@@ -7112,10 +7112,10 @@
                     function Engine() {}
                     return(// eslint-disable-next-line
                     Engine.prototype.compile = function(templateString, helper, ignorePrefix) {
-                        var helper1, argName, str, nameSpace, helper2, ignorePrefix1, varCOunt, localKeys, isClass, singleSpace;
-                        return void 0 === helper && (helper = {}), str = templateString, nameSpace = argName = 'data', helper2 = helper1 = helper, ignorePrefix1 = void 0, varCOunt = 0, localKeys = [], isClass = str.match(/class="([^"]+|)\s{2}/g), singleSpace = '', isClass && isClass.forEach(function(value) {
+                        var helper1, str, nameSpace, helper2, ignorePrefix1, varCOunt, localKeys, isClass, singleSpace;
+                        return void 0 === helper && (helper = {}), str = templateString, nameSpace = 'data', helper2 = helper1 = helper, ignorePrefix1 = void 0, varCOunt = 0, localKeys = [], isClass = str.match(/class="([^"]+|)\s{2}/g), singleSpace = '', isClass && isClass.forEach(function(value) {
                             singleSpace = value.replace(/\s\s+/g, ' '), str = str.replace(value, singleSpace);
-                        }), Function(argName, "var str=\"" + str.replace(LINES, '').replace(DBL_QUOTED_STR, '\'$1\'').replace(exp, // eslint-disable-next-line
+                        }), Function('data', "var str=\"" + str.replace(LINES, '').replace(DBL_QUOTED_STR, '\'$1\'').replace(exp, // eslint-disable-next-line
                         function(match, cnt, offset, matchStr) {
                             var matches = cnt.match(CALL_FUNCTION);
                             // matches to detect any function calls