feat(es/minifier): Inline pure array literal partially

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

@@ -1,9 +1,6 @@
 //// [bitwiseNotOperatorWithAnyOtherType.ts]
 import _class_call_check from "@swc/helpers/src/_class_call_check.mjs";
-var M, ANY2 = [
-    "",
-    ""
-], obj1 = {
+var M, obj1 = {
     x: "",
     y: function() {}
 }, A = function() {
@@ -18,4 +15,4 @@ var M, ANY2 = [
     M.n = n;
 }(M || (M = {}));
 var objA = new A();
-ANY2[0], obj1.x, obj1.y, objA.a, M.n, A.foo(), ANY2[0], obj1.y, objA.a, M.n, obj1.x;
+obj1.x, obj1.y, objA.a, M.n, A.foo(), obj1.y, objA.a, M.n, obj1.x;

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

@@ -1,7 +1 @@
 //// [conditionalOperatorConditionIsNumberType.ts]
-var array = [
-    1,
-    2,
-    3
-];
-array[1], array[1], array[1];

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

@@ -1,11 +1,7 @@
 //// [conditionalOperatorConditoinIsStringType.ts]
+var condString;
 import _type_of from "@swc/helpers/src/_type_of.mjs";
 function foo() {
     return "string";
 }
-var condString, array = [
-    "1",
-    "2",
-    "3"
-];
-void 0 === condString || _type_of(condString), condString.toUpperCase, foo(), array[1], foo(), void 0 === condString || _type_of(condString), condString.toUpperCase, foo(), array[1], void 0 === condString || _type_of(condString), condString.toUpperCase;
+void 0 === condString || _type_of(condString), condString.toUpperCase, foo(), foo(), void 0 === condString || _type_of(condString), condString.toUpperCase, foo(), void 0 === condString || _type_of(condString), condString.toUpperCase;

crates/swc/tests/tsc-references/destructuringArrayBindingPatternAndAssignment2.2.minified.js

@@ -1,25 +1,25 @@
 //// [destructuringArrayBindingPatternAndAssignment2.ts]
 import _sliced_to_array from "@swc/helpers/src/_sliced_to_array.mjs";
 import _to_consumable_array from "@swc/helpers/src/_to_consumable_array.mjs";
-var ref = [], ref1 = (_sliced_to_array(ref[0], 1)[0], _sliced_to_array(ref[1], 1));
+var ref = (_sliced_to_array([][0], 1)[0], _sliced_to_array([][1], 1));
+_sliced_to_array(ref[0], 1)[0];
+var _undefined = _sliced_to_array(void 0, 2), ref1 = (_sliced_to_array(_undefined[0], 1)[0], _sliced_to_array(_undefined[1], 1));
 _sliced_to_array(ref1[0], 1)[0];
-var _undefined = _sliced_to_array(void 0, 2), ref2 = (_sliced_to_array(_undefined[0], 1)[0], _sliced_to_array(_undefined[1], 1));
-_sliced_to_array(ref2[0], 1)[0];
-var ref3 = _sliced_to_array([
+var ref2 = _sliced_to_array([
     1,
     2,
     3
 ], 3);
-ref3[0], ref3[1], ref3[2];
+ref2[0], ref2[1], ref2[2];
 var temp = [
     1,
     2,
     3
-], ref4 = _sliced_to_array(_to_consumable_array(temp), 2);
+], ref3 = _sliced_to_array(_to_consumable_array(temp), 2);
+ref3[0], ref3[1];
+var ref4 = _sliced_to_array(_to_consumable_array(temp), 2);
 ref4[0], ref4[1];
-var ref5 = _sliced_to_array(_to_consumable_array(temp), 2);
-ref5[0], ref5[1];
-var ref6 = _sliced_to_array({
+var ref5 = _sliced_to_array({
     2: !0
 }, 3);
-ref6[0], ref6[1], ref6[2];
+ref5[0], ref5[1], ref5[2];

crates/swc/tests/tsc-references/destructuringArrayBindingPatternAndAssignment3.2.minified.js

@@ -1,15 +1,9 @@
 //// [destructuringArrayBindingPatternAndAssignment3.ts]
 import _sliced_to_array from "@swc/helpers/src/_sliced_to_array.mjs";
-var ref = [
+var tmp = [
     1
-];
-ref[0], ref[1];
-var ref1 = [
-    1
-], tmp = (ref1[0], ref1[1], ref1[2]), e = void 0 === tmp ? e : tmp, ref2 = [
-    1
-];
-ref2[0], ref2[1], ref2[2], ref2[3], function(param) {
+][2], e = void 0 === tmp ? e : tmp;
+!function(param) {
     var _param = _sliced_to_array(param, 2);
     _param[0], _param[1];
 }([

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

@@ -1,5 +1,4 @@
 //// [destructuringControlFlow.ts]
-var ref = [
+(0, [
     "foo"
-];
-(ref[0], ref[1]).toUpperCase();
+][1]).toUpperCase();

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

@@ -15,4 +15,4 @@ var strNumTuple = [
     !0,
     "foo"
 ];
-strNumTuple[0], strNumTuple[1], strNumTuple[2], strNumTuple[0], strNumTuple[1], strNumTuple["0"], strNumTuple["1"], numTupleTuple[1], numTupleTuple[2], strNumTuple[-1], unionTuple1[0], unionTuple1[1], unionTuple1[2], unionTuple1[0], unionTuple1[1], unionTuple1["0"], unionTuple1["1"], unionTuple2[0], unionTuple2[1], unionTuple2[2], unionTuple2[0], unionTuple2[1], unionTuple2["0"], unionTuple2["1"];
+strNumTuple["0"], strNumTuple["1"], numTupleTuple[1], numTupleTuple[2], unionTuple1["0"], unionTuple1["1"], unionTuple2[0], unionTuple2[1], unionTuple2[2], unionTuple2[0], unionTuple2[1], unionTuple2["0"], unionTuple2["1"];

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

@@ -1,9 +1,6 @@
 //// [logicalNotOperatorWithAnyOtherType.ts]
 import _class_call_check from "@swc/helpers/src/_class_call_check.mjs";
-var M, ANY2 = [
-    "",
-    ""
-], obj1 = {
+var M, obj1 = {
     x: "",
     y: function() {}
 }, A = function() {
@@ -18,4 +15,4 @@ var M, ANY2 = [
     M.n = n;
 }(M || (M = {}));
 var objA = new A();
-ANY2[0], obj1.x, obj1.y, objA.a, M.n, A.foo(), ANY2[0], objA.a, M.n;
+obj1.x, obj1.y, objA.a, M.n, A.foo(), objA.a, M.n;

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

@@ -1,9 +1,6 @@
 //// [negateOperatorWithAnyOtherType.ts]
 import _class_call_check from "@swc/helpers/src/_class_call_check.mjs";
-var M, ANY2 = [
-    "",
-    ""
-], obj1 = {
+var M, obj1 = {
     x: "",
     y: function() {}
 }, A = function() {
@@ -18,4 +15,4 @@ var M, ANY2 = [
     M.n = n;
 }(M || (M = {}));
 var objA = new A();
-ANY2[0], obj1.x, obj1.y, objA.a, M.n, A.foo(), ANY2[0], objA.a, M.n;
+obj1.x, obj1.y, objA.a, M.n, A.foo(), objA.a, M.n;

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

@@ -1,9 +1,6 @@
 //// [plusOperatorWithAnyOtherType.ts]
 import _class_call_check from "@swc/helpers/src/_class_call_check.mjs";
-var M, ANY2 = [
-    "",
-    ""
-], obj1 = {
+var M, obj1 = {
     x: function(s) {},
     y: function(s1) {}
 }, A = function() {
@@ -18,4 +15,4 @@ var M, ANY2 = [
     M.n = n;
 }(M || (M = {}));
 var objA = new A();
-ANY2[0], obj1.x, obj1.y, objA.a, M.n, A.foo(), ANY2[0], objA.a, M.n;
+obj1.x, obj1.y, objA.a, M.n, A.foo(), objA.a, M.n;

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

@@ -1,9 +1,4 @@
 //// [typeInferenceWithTupleType.ts]
-var combineResult = [
-    "string",
-    10
-];
-combineResult[0], combineResult[1];
 var zipResult = function(array1, array2) {
     if (array1.length != array2.length) return [
         [

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

@@ -1,9 +1,6 @@
 //// [voidOperatorWithAnyOtherType.ts]
 import _class_call_check from "@swc/helpers/src/_class_call_check.mjs";
-var M, ANY2 = [
-    "",
-    ""
-], obj1 = {
+var M, obj1 = {
     x: "",
     y: 1
 }, A = function() {
@@ -18,4 +15,4 @@ var M, ANY2 = [
     M.n = n;
 }(M || (M = {}));
 var objA = new A();
-ANY2[0], obj1.x, obj1.y, objA.a, M.n, A.foo(), ANY2[0], objA.a, M.n;
+obj1.x, obj1.y, objA.a, M.n, A.foo(), objA.a, M.n;

crates/swc_ecma_minifier/src/analyzer/mod.rs

@@ -137,6 +137,7 @@ pub(crate) struct VarUsageInfo {
     infects: Vec<Access>,
 
     pub used_in_non_child_fn: bool,
+    /// Only **string** properties.
     pub accessed_props: Box<AHashMap<JsWord, u32>>,
 
     pub used_recursively: bool,

crates/swc_ecma_minifier/src/analyzer/storage/normal.rs

@@ -104,6 +104,10 @@ impl Storage for ProgramData {
                     e.get_mut().is_fn_local &= var_info.is_fn_local;
                     e.get_mut().used_in_non_child_fn |= var_info.used_in_non_child_fn;
 
+                    for (k, v) in *var_info.accessed_props {
+                        *e.get_mut().accessed_props.entry(k).or_default() += v;
+                    }
+
                     match kind {
                         ScopeKind::Fn => {
                             e.get_mut().is_fn_local = false;

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

@@ -89,8 +89,42 @@ where
                 return;
             }
 
+            let is_inline_enabled =
+                self.options.reduce_vars || self.options.collapse_vars || self.options.inline != 0;
+
             self.vars.inline_with_multi_replacer(init);
 
+            // We inline arrays partially if it's pure (all elements are literal), and not
+            // modified.
+            // We don't drop definition, but we just inline array accesses with numeric
+            // literal key.
+            //
+            // TODO: Allow `length` in usage.accessed_props
+            if usage.declared
+                && !usage.reassigned()
+                && !usage.mutated
+                && !usage.has_property_mutation
+                && usage.accessed_props.is_empty()
+                && !usage.is_infected()
+                && is_inline_enabled
+            {
+                if let Expr::Array(arr) = init {
+                    if arr.elems.len() < 32
+                        && arr.elems.iter().all(|e| match e {
+                            Some(ExprOrSpread { spread: None, expr }) => match &**expr {
+                                Expr::Lit(..) => true,
+                                _ => false,
+                            },
+                            _ => false,
+                        })
+                    {
+                        self.vars
+                            .lits_for_array_access
+                            .insert(ident.to_id(), Box::new(init.clone()));
+                    }
+                }
+            }
+
             if !usage.is_fn_local {
                 match init {
                     Expr::Lit(..) | Expr::Ident(..) => {}
@@ -133,9 +167,6 @@ where
                 self.mode.store(ident.to_id(), &*init);
             }
 
-            let is_inline_enabled =
-                self.options.reduce_vars || self.options.collapse_vars || self.options.inline != 0;
-
             // Mutation of properties are ok
             if is_inline_enabled
                 && usage.declared_count == 1

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

@@ -246,6 +246,9 @@ struct Vars {
     /// https://github.com/swc-project/swc/issues/4415
     lits_for_cmp: FxHashMap<Id, Box<Expr>>,
 
+    /// This stores [Expr::Array] if all elements are literals.
+    lits_for_array_access: FxHashMap<Id, Box<Expr>>,
+
     /// Used for copying functions.
     ///
     /// We use this to distinguish [Callee::Expr] from other [Expr]s.
@@ -271,11 +274,13 @@ impl Vars {
         let mut changed = false;
         if !self.simple_functions.is_empty()
             || !self.lits_for_cmp.is_empty()
+            || !self.lits_for_array_access.is_empty()
             || !self.removed.is_empty()
         {
             let mut v = Finalizer {
                 simple_functions: &self.simple_functions,
                 lits_for_cmp: &self.lits_for_cmp,
+                lits_for_array_access: &self.lits_for_array_access,
                 vars_to_remove: &self.removed,
                 changed: false,
             };

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

@@ -164,6 +164,7 @@ impl VisitMut for Remapper {
 pub(crate) struct Finalizer<'a> {
     pub simple_functions: &'a FxHashMap<Id, Box<Expr>>,
     pub lits_for_cmp: &'a FxHashMap<Id, Box<Expr>>,
+    pub lits_for_array_access: &'a FxHashMap<Id, Box<Expr>>,
 
     pub vars_to_remove: &'a FxHashSet<Id>,
 
@@ -183,8 +184,9 @@ impl Parallel for Finalizer<'_> {
 impl<'a> Finalizer<'a> {
     fn var(&mut self, i: &Id, mode: FinalizerMode) -> Option<Box<Expr>> {
         let mut e = match mode {
-            FinalizerMode::OnlyCallee => self.simple_functions.get(i).cloned()?,
-            FinalizerMode::OnlyComparisonWithLit => self.lits_for_cmp.get(i).cloned()?,
+            FinalizerMode::Callee => self.simple_functions.get(i).cloned()?,
+            FinalizerMode::ComparisonWithLit => self.lits_for_cmp.get(i).cloned()?,
+            FinalizerMode::MemberAccess => self.lits_for_array_access.get(i).cloned()?,
         };
 
         e.visit_mut_children_with(self);
@@ -215,8 +217,9 @@ impl<'a> Finalizer<'a> {
 
 #[derive(Debug, Clone, Copy)]
 enum FinalizerMode {
-    OnlyCallee,
-    OnlyComparisonWithLit,
+    Callee,
+    ComparisonWithLit,
+    MemberAccess,
 }
 
 impl VisitMut for Finalizer<'_> {
@@ -226,7 +229,17 @@ impl VisitMut for Finalizer<'_> {
         e.visit_mut_children_with(self);
 
         if let Callee::Expr(e) = e {
-            self.check(e, FinalizerMode::OnlyCallee);
+            self.check(e, FinalizerMode::Callee);
+        }
+    }
+
+    fn visit_mut_member_expr(&mut self, e: &mut MemberExpr) {
+        e.visit_mut_children_with(self);
+
+        if let MemberProp::Computed(ref mut prop) = e.prop {
+            if let Expr::Lit(Lit::Num(..)) = &*prop.expr {
+                self.check(&mut e.obj, FinalizerMode::MemberAccess);
+            }
         }
     }
 
@@ -237,9 +250,9 @@ impl VisitMut for Finalizer<'_> {
             op!("===") | op!("!==") | op!("==") | op!("!=") => {
                 //
                 if e.left.is_lit() {
-                    self.check(&mut e.right, FinalizerMode::OnlyComparisonWithLit);
+                    self.check(&mut e.right, FinalizerMode::ComparisonWithLit);
                 } else if e.right.is_lit() {
-                    self.check(&mut e.left, FinalizerMode::OnlyComparisonWithLit);
+                    self.check(&mut e.left, FinalizerMode::ComparisonWithLit);
                 }
             }
             _ => {}

crates/swc_ecma_minifier/tests/TODO.txt

@@ -3,7 +3,6 @@ arrays/constant_join/input.js
 arrays/constant_join_2/input.js
 arrays/constant_join_3/input.js
 arrays/for_loop/input.js
-arrays/index/input.js
 arrays/index_length/input.js
 arrow/issue_2084/input.js
 arrow/issue_2105_1/input.js

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

@@ -28249,10 +28249,7 @@
         seriesType: 'candlestick',
         plan: createRenderPlanner(),
         reset: function(seriesModel) {
-            var seriesModel1, data, extent, baseAxis, bandWidth, barMaxWidth, barMinWidth, barWidth, coordSys = seriesModel.coordinateSystem, data1 = seriesModel.getData(), candleWidth = (seriesModel1 = seriesModel, data = data1, bandWidth = 'category' === (baseAxis = seriesModel1.getBaseAxis()).type ? baseAxis.getBandWidth() : Math.abs((extent = baseAxis.getExtent())[1] - extent[0]) / data.count(), barMaxWidth = parsePercent$1(retrieve2(seriesModel1.get('barMaxWidth'), bandWidth), bandWidth), barMinWidth = parsePercent$1(retrieve2(seriesModel1.get('barMinWidth'), 1), bandWidth), null != (barWidth = seriesModel1.get('barWidth')) ? parsePercent$1(barWidth, bandWidth) : Math.max(Math.min(bandWidth / 2, barMaxWidth), barMinWidth)), coordDims = [
-                'x',
-                'y'
-            ], cDim = data1.mapDimension(coordDims[0]), vDims = data1.mapDimensionsAll(coordDims[1]), openDim = vDims[0], closeDim = vDims[1], lowestDim = vDims[2], highestDim = vDims[3];
+            var seriesModel1, data, extent, baseAxis, bandWidth, barMaxWidth, barMinWidth, barWidth, coordSys = seriesModel.coordinateSystem, data1 = seriesModel.getData(), candleWidth = (seriesModel1 = seriesModel, data = data1, bandWidth = 'category' === (baseAxis = seriesModel1.getBaseAxis()).type ? baseAxis.getBandWidth() : Math.abs((extent = baseAxis.getExtent())[1] - extent[0]) / data.count(), barMaxWidth = parsePercent$1(retrieve2(seriesModel1.get('barMaxWidth'), bandWidth), bandWidth), barMinWidth = parsePercent$1(retrieve2(seriesModel1.get('barMinWidth'), 1), bandWidth), null != (barWidth = seriesModel1.get('barWidth')) ? parsePercent$1(barWidth, bandWidth) : Math.max(Math.min(bandWidth / 2, barMaxWidth), barMinWidth)), cDim = data1.mapDimension('x'), vDims = data1.mapDimensionsAll('y'), openDim = vDims[0], closeDim = vDims[1], lowestDim = vDims[2], highestDim = vDims[3];
             if (data1.setLayout({
                 candleWidth: candleWidth,
                 isSimpleBox: candleWidth <= 1.3
@@ -39656,10 +39653,7 @@
                 color: '#333'
             }
         }, VisualMapModel;
-    }(ComponentModel), DEFAULT_BAR_BOUND = [
-        20,
-        140
-    ], ContinuousModel = function(_super) {
+    }(ComponentModel), ContinuousModel = function(_super) {
         function ContinuousModel() {
             var _this = null !== _super && _super.apply(this, arguments) || this;
             return _this.type = ContinuousModel.type, _this;
@@ -39671,7 +39665,7 @@
         }, ContinuousModel.prototype.resetItemSize = function() {
             _super.prototype.resetItemSize.apply(this, arguments);
             var itemSize = this.itemSize;
-            (null == itemSize[0] || isNaN(itemSize[0])) && (itemSize[0] = DEFAULT_BAR_BOUND[0]), (null == itemSize[1] || isNaN(itemSize[1])) && (itemSize[1] = DEFAULT_BAR_BOUND[1]);
+            (null == itemSize[0] || isNaN(itemSize[0])) && (itemSize[0] = 20), (null == itemSize[1] || isNaN(itemSize[1])) && (itemSize[1] = 140);
         }, ContinuousModel.prototype._resetRange = function() {
             var dataExtent = this.getExtent(), range = this.option.range;
             !range || range.auto ? (dataExtent.auto = 1, this.option.range = dataExtent) : isArray(range) && (range[0] > range[1] && range.reverse(), range[0] = Math.max(range[0], dataExtent[0]), range[1] = Math.min(range[1], dataExtent[1]));