feat(minifier): support more statements for single use variable inlining

crates/oxc_minifier/src/peephole/minimize_statements.rs

@@ -374,11 +374,21 @@ impl<'a> PeepholeOptimizations {
     /// * remove the variable declarator if it is unused
     /// * keep the initializer if it has side effects
     fn handle_variable_declaration(
-        var_decl: Box<'a, VariableDeclaration<'a>>,
+        mut var_decl: Box<'a, VariableDeclaration<'a>>,
         result: &mut Vec<'a, Statement<'a>>,
 
         ctx: &mut Ctx<'a, '_>,
     ) {
+        if let Some(first_decl) = var_decl.declarations.first_mut()
+            && let Some(first_decl_init) = first_decl.init.as_mut()
+        {
+            let changed =
+                Self::substitute_single_use_symbol_in_statement(first_decl_init, result, ctx);
+            if changed {
+                ctx.state.changed = true;
+            }
+        }
+
         // If `join_vars` is off, but there are unused declarators ... just join them to make our code simpler.
         if !ctx.options().join_vars
             && var_decl.declarations.iter().all(|d| !Self::should_remove_unused_declarator(d, ctx))
@@ -421,6 +431,12 @@ impl<'a> PeepholeOptimizations {
 
         ctx: &mut Ctx<'a, '_>,
     ) {
+        let changed =
+            Self::substitute_single_use_symbol_in_statement(&mut expr_stmt.expression, result, ctx);
+        if changed {
+            ctx.state.changed = true;
+        }
+
         if ctx.options().sequences {
             if let Some(Statement::ExpressionStatement(prev_expr_stmt)) = result.last_mut() {
                 let a = &mut prev_expr_stmt.expression;
@@ -439,6 +455,15 @@ impl<'a> PeepholeOptimizations {
 
         ctx: &mut Ctx<'a, '_>,
     ) {
+        let changed = Self::substitute_single_use_symbol_in_statement(
+            &mut switch_stmt.discriminant,
+            result,
+            ctx,
+        );
+        if changed {
+            ctx.state.changed = true;
+        }
+
         if ctx.options().sequences {
             if let Some(Statement::ExpressionStatement(prev_expr_stmt)) = result.last_mut() {
                 let a = &mut prev_expr_stmt.expression;
@@ -460,6 +485,12 @@ impl<'a> PeepholeOptimizations {
 
         ctx: &mut Ctx<'a, '_>,
     ) -> ControlFlow<()> {
+        let changed =
+            Self::substitute_single_use_symbol_in_statement(&mut if_stmt.test, result, ctx);
+        if changed {
+            ctx.state.changed = true;
+        }
+
         // Absorb a previous expression statement
         if ctx.options().sequences {
             if let Some(Statement::ExpressionStatement(prev_expr_stmt)) = result.last_mut() {
@@ -666,6 +697,12 @@ impl<'a> PeepholeOptimizations {
 
         ctx: &mut Ctx<'a, '_>,
     ) {
+        let changed =
+            Self::substitute_single_use_symbol_in_statement(&mut throw_stmt.argument, result, ctx);
+        if changed {
+            ctx.state.changed = true;
+        }
+
         if ctx.options().sequences {
             if let Some(Statement::ExpressionStatement(prev_expr_stmt)) = result.last_mut() {
                 let a = &mut prev_expr_stmt.expression;

crates/oxc_minifier/tests/peephole/esbuild.rs

@@ -1957,14 +1957,14 @@ fn test_inline_single_use_variable() {
         "function wrapper(arg0, arg1) { let x = fn(); return arg0 ?? x;}",
         "function wrapper(arg0, arg1) { let x = fn(); return arg0 ?? x;}",
     );
-    // test(
-    //     "function wrapper(arg0, arg1) { let x = fn(); let y = x[prop]; let z = y.val; throw z}",
-    //     "function wrapper(arg0, arg1) { throw fn()[prop].val;}",
-    // );
-    // test(
-    //     "function wrapper(arg0, arg1) { let x = fn(), y = x[prop], z = y.val; throw z}",
-    //     "function wrapper(arg0, arg1) { throw fn()[prop].val;}",
-    // );
+    test(
+        "function wrapper(arg0, arg1) { let x = fn(); let y = x[prop]; let z = y.val; throw z}",
+        "function wrapper(arg0, arg1) { throw fn()[prop].val;}",
+    );
+    test(
+        "function wrapper(arg0, arg1) { let x = fn(), y = x[prop], z = y.val; throw z}",
+        "function wrapper(arg0, arg1) { throw fn()[prop].val;}",
+    );
     test(
         "function wrapper(arg0, arg1) { let x = fn(); let y = x[prop]; let z = y.val; return z}",
         "function wrapper(arg0, arg1) { return fn()[prop].val;}",
@@ -2014,42 +2014,42 @@ fn test_inline_single_use_variable() {
         "function wrapper(arg0, arg1) { let x = arg0; return arg1(...arg1, x);}",
         "function wrapper(arg0, arg1) { let x = arg0; return arg1(...arg1, x);}",
     );
-    // test(
-    //     "function wrapper(arg0, arg1) { let x = arg0; arg1(x);}",
-    //     "function wrapper(arg0, arg1) { arg1(arg0);}",
-    // );
-    // test(
-    //     "function wrapper(arg0, arg1) { let x = arg0; throw x;}",
-    //     "function wrapper(arg0, arg1) { throw arg0;}",
-    // );
+    test(
+        "function wrapper(arg0, arg1) { let x = arg0; arg1(x);}",
+        "function wrapper(arg0, arg1) { arg1(arg0);}",
+    );
+    test(
+        "function wrapper(arg0, arg1) { let x = arg0; throw x;}",
+        "function wrapper(arg0, arg1) { throw arg0;}",
+    );
     test(
         "function wrapper(arg0, arg1) { let x = arg0; return x;}",
         "function wrapper(arg0, arg1) { return arg0;}",
     );
-    // test(
-    //     "function wrapper(arg0, arg1) { let x = arg0; if (x) return 1;}",
-    //     "function wrapper(arg0, arg1) { if (arg0) return 1;}",
-    // );
-    // test(
-    //     "function wrapper(arg0, arg1) { let x = arg0; switch (x) { case 0: return 1; }}",
-    //     "function wrapper(arg0, arg1) { switch (arg0) { case 0:  return 1; }}",
-    // );
-    // test(
-    //     "function wrapper(arg0, arg1) { let x = arg0; let y = x; return y + y;}",
-    //     "function wrapper(arg0, arg1) { let y = arg0; return y + y;}",
-    // );
-    // test(
-    //     "function wrapper(arg0, arg1) { let x = arg0; do {} while (x);}",
-    //     "function wrapper(arg0, arg1) { let x = arg0; do ; while (x);}",
-    // );
-    // test(
-    //     "function wrapper(arg0, arg1) { let x = arg0; while (x) return 1;}",
-    //     "function wrapper(arg0, arg1) { let x = arg0; for (; x; ) return 1;}",
-    // );
-    // test(
-    //     "function wrapper(arg0, arg1) { let x = arg0; for (; x; ) return 1;}",
-    //     "function wrapper(arg0, arg1) { let x = arg0; for (; x; ) return 1;}",
-    // );
+    test(
+        "function wrapper(arg0, arg1) { let x = arg0; if (x) return 1;}",
+        "function wrapper(arg0, arg1) { if (arg0) return 1;}",
+    );
+    test(
+        "function wrapper(arg0, arg1) { let x = arg0; switch (x) { case 0: return 1; }}",
+        "function wrapper(arg0, arg1) { switch (arg0) { case 0:  return 1; }}",
+    );
+    test(
+        "function wrapper(arg0, arg1) { let x = arg0; let y = x; return y + y;}",
+        "function wrapper(arg0, arg1) { let y = arg0; return y + y;}",
+    );
+    test(
+        "function wrapper(arg0, arg1) { let x = arg0; do {} while (x);}",
+        "function wrapper(arg0, arg1) { let x = arg0; do ; while (x);}",
+    );
+    test(
+        "function wrapper(arg0, arg1) { let x = arg0; while (x) return 1;}",
+        "function wrapper(arg0, arg1) { let x = arg0; for (; x; ) return 1;}",
+    );
+    test(
+        "function wrapper(arg0, arg1) { let x = arg0; for (; x; ) return 1;}",
+        "function wrapper(arg0, arg1) { let x = arg0; for (; x; ) return 1;}",
+    );
     test(
         "function wrapper(arg0, arg1) { let x = arg0; return arg1?.[x];}",
         "function wrapper(arg0, arg1) { return arg1?.[arg0];}",
@@ -2186,10 +2186,10 @@ fn test_inline_single_use_variable() {
         "function wrapper(arg0, arg1) { let x = arg0; return [import(arg1), x];}",
         "function wrapper(arg0, arg1) { return [import(arg1), arg0];}",
     );
-    // test(
-    //     "function wrapper(arg0, arg1) {return async () => { let x = arg0; await x; };}",
-    //     "function wrapper(arg0, arg1) { return async () => { await arg0; };}",
-    // );
+    test(
+        "function wrapper(arg0, arg1) {return async () => { let x = arg0; await x; };}",
+        "function wrapper(arg0, arg1) { return async () => { await arg0; };}",
+    );
     test(
         "function wrapper(arg0, arg1) {return async () => { let x = arg0; await y; return x; };}",
         "function wrapper(arg0, arg1) { return async () => { let x = arg0; return await y, x; };}",
@@ -2198,10 +2198,10 @@ fn test_inline_single_use_variable() {
         "function wrapper(arg0, arg1) {return async () => { let x = arg0; await arg1; return x; };}",
         "function wrapper(arg0, arg1) { return async () => { let x = arg0; return await arg1, x; };}",
     );
-    // test(
-    //     "function wrapper(arg0, arg1) {return function* () { let x = arg0; yield x; };}",
-    //     "function wrapper(arg0, arg1) { return function* () { yield arg0; };}",
-    // );
+    test(
+        "function wrapper(arg0, arg1) {return function* () { let x = arg0; yield x; };}",
+        "function wrapper(arg0, arg1) { return function* () { yield arg0; };}",
+    );
     test(
         "function wrapper(arg0, arg1) {return function* () { let x = arg0; yield; return x; };}",
         "function wrapper(arg0, arg1) { return function* () { let x = arg0; return yield, x; };}",
@@ -2214,70 +2214,70 @@ fn test_inline_single_use_variable() {
         "function wrapper(arg0, arg1) {return function* () { let x = arg0; yield arg1; return x; };}",
         "function wrapper(arg0, arg1) { return function* () { let x = arg0; return yield arg1, x; };}",
     );
-    // test(
-    //     "function wrapper(arg0, arg1) { let x = arg0; x()}",
-    //     "function wrapper(arg0, arg1) { arg0();}",
-    // );
-    // test(
-    //     "function wrapper(arg0, arg1) { let x = arg0; (0, x)()}",
-    //     "function wrapper(arg0, arg1) { arg0();}",
-    // );
-    // test(
-    //     "function wrapper(arg0, arg1) { let x = arg0.foo; x.bar()}",
-    //     "function wrapper(arg0, arg1) { arg0.foo.bar();}",
-    // );
-    // test(
-    //     "function wrapper(arg0, arg1) { let x = arg0.foo; x[bar]()}",
-    //     "function wrapper(arg0, arg1) { arg0.foo[bar]();}",
-    // );
-    // test(
-    //     "function wrapper(arg0, arg1) { let x = arg0.foo; x()}",
-    //     "function wrapper(arg0, arg1) { let x = arg0.foo; x();}",
-    // );
-    // test(
-    //     "function wrapper(arg0, arg1) { let x = arg0[foo]; x()}",
-    //     "function wrapper(arg0, arg1) { let x = arg0[foo]; x();}",
-    // );
-    // test(
-    //     "function wrapper(arg0, arg1) { let x = arg0?.foo; x()}",
-    //     "function wrapper(arg0, arg1) { let x = arg0?.foo; x();}",
-    // );
-    // test(
-    //     "function wrapper(arg0, arg1) { let x = arg0?.[foo]; x()}",
-    //     "function wrapper(arg0, arg1) { let x = arg0?.[foo]; x();}",
-    // );
-    // test(
-    //     "function wrapper(arg0, arg1) { let x = arg0.foo; (0, x)()}",
-    //     "function wrapper(arg0, arg1) { let x = arg0.foo; x();}",
-    // );
-    // test(
-    //     "function wrapper(arg0, arg1) { let x = arg0[foo]; (0, x)()}",
-    //     "function wrapper(arg0, arg1) { let x = arg0[foo]; x();}",
-    // );
-    // test(
-    //     "function wrapper(arg0, arg1) { let x = arg0?.foo; (0, x)()}",
-    //     "function wrapper(arg0, arg1) { let x = arg0?.foo; x();}",
-    // );
-    // test(
-    //     "function wrapper(arg0, arg1) { let x = arg0?.[foo]; (0, x)()}",
-    //     "function wrapper(arg0, arg1) { let x = arg0?.[foo]; x();}",
-    // );
-    // test(
-    //     "function wrapper(arg0, arg1) { let x = arg0(); arg1() + x}",
-    //     "function wrapper(arg0, arg1) { let x = arg0(); arg1() + x;}",
-    // );
-    // test(
-    //     "function wrapper(arg0, arg1) { let x = arg0(); /* @__PURE__ */ arg1() + x}",
-    //     "function wrapper(arg0, arg1) { let x = arg0(); /* @__PURE__ */ arg1() + x;}",
-    // );
-    // test(
-    //     "function wrapper(arg0, arg1) { let x = /* @__PURE__ */ arg0(); arg1() + x}",
-    //     "function wrapper(arg0, arg1) { let x = /* @__PURE__ */ arg0(); arg1() + x;}",
-    // );
-    // test(
-    //     "function wrapper(arg0, arg1) { let x = /* @__PURE__ */ arg0(); /* @__PURE__ */ arg1() + x}",
-    //     "function wrapper(arg0, arg1) { /* @__PURE__ */ arg1() + /* @__PURE__ */ arg0();}",
-    // );
+    test(
+        "function wrapper(arg0, arg1) { let x = arg0; x()}",
+        "function wrapper(arg0, arg1) { arg0();}",
+    );
+    test(
+        "function wrapper(arg0, arg1) { let x = arg0; (0, x)()}",
+        "function wrapper(arg0, arg1) { arg0();}",
+    );
+    test(
+        "function wrapper(arg0, arg1) { let x = arg0.foo; x.bar()}",
+        "function wrapper(arg0, arg1) { arg0.foo.bar();}",
+    );
+    test(
+        "function wrapper(arg0, arg1) { let x = arg0.foo; x[bar]()}",
+        "function wrapper(arg0, arg1) { arg0.foo[bar]();}",
+    );
+    test(
+        "function wrapper(arg0, arg1) { let x = arg0.foo; x()}",
+        "function wrapper(arg0, arg1) { let x = arg0.foo; x();}",
+    );
+    test(
+        "function wrapper(arg0, arg1) { let x = arg0[foo]; x()}",
+        "function wrapper(arg0, arg1) { let x = arg0[foo]; x();}",
+    );
+    test(
+        "function wrapper(arg0, arg1) { let x = arg0?.foo; x()}",
+        "function wrapper(arg0, arg1) { let x = arg0?.foo; x();}",
+    );
+    test(
+        "function wrapper(arg0, arg1) { let x = arg0?.[foo]; x()}",
+        "function wrapper(arg0, arg1) { let x = arg0?.[foo]; x();}",
+    );
+    test(
+        "function wrapper(arg0, arg1) { let x = arg0.foo; (0, x)()}",
+        "function wrapper(arg0, arg1) { let x = arg0.foo; x();}",
+    );
+    test(
+        "function wrapper(arg0, arg1) { let x = arg0[foo]; (0, x)()}",
+        "function wrapper(arg0, arg1) { let x = arg0[foo]; x();}",
+    );
+    test(
+        "function wrapper(arg0, arg1) { let x = arg0?.foo; (0, x)()}",
+        "function wrapper(arg0, arg1) { let x = arg0?.foo; x();}",
+    );
+    test(
+        "function wrapper(arg0, arg1) { let x = arg0?.[foo]; (0, x)()}",
+        "function wrapper(arg0, arg1) { let x = arg0?.[foo]; x();}",
+    );
+    test(
+        "function wrapper(arg0, arg1) { let x = arg0(); arg1() + x}",
+        "function wrapper(arg0, arg1) { let x = arg0(); arg1() + x;}",
+    );
+    test(
+        "function wrapper(arg0, arg1) { let x = arg0(); /* @__PURE__ */ arg1() + x}",
+        "function wrapper(arg0, arg1) { let x = arg0(); /* @__PURE__ */ arg1() + x;}",
+    );
+    test(
+        "function wrapper(arg0, arg1) { let x = /* @__PURE__ */ arg0(); arg1() + x}",
+        "function wrapper(arg0, arg1) { let x = /* @__PURE__ */ arg0(); arg1() + x;}",
+    );
+    test(
+        "function wrapper(arg0, arg1) { let x = /* @__PURE__ */ arg0(); /* @__PURE__ */ arg1() + x}",
+        "function wrapper(arg0, arg1) { /* @__PURE__ */ arg1() + /* @__PURE__ */ arg0();}",
+    );
 }
 
 #[test]

tasks/minsize/minsize.snap

@@ -1,27 +1,27 @@
            | Oxc        | ESBuild    | Oxc        | ESBuild    |
 Original   | minified   | minified   | gzip       | gzip       | Iterations | File      
 -------------------------------------------------------------------------------------
-72.14 kB   | 23.23 kB   | 23.70 kB   | 8.40 kB    | 8.54 kB    |          2 | react.development.js 
+72.14 kB   | 23.22 kB   | 23.70 kB   | 8.39 kB    | 8.54 kB    |          2 | react.development.js 
 
 173.90 kB  | 59.47 kB   | 59.82 kB   | 19.18 kB   | 19.33 kB   |          2 | moment.js  
 
-287.63 kB  | 89.31 kB   | 90.07 kB   | 30.95 kB   | 31.95 kB   |          2 | jquery.js  
+287.63 kB  | 89.29 kB   | 90.07 kB   | 30.95 kB   | 31.95 kB   |          2 | jquery.js  
 
-342.15 kB  | 117.17 kB  | 118.14 kB  | 43.27 kB   | 44.37 kB   |          2 | vue.js     
+342.15 kB  | 117.02 kB  | 118.14 kB  | 43.19 kB   | 44.37 kB   |          2 | vue.js     
 
-544.10 kB  | 71.20 kB   | 72.48 kB   | 25.85 kB   | 26.20 kB   |          3 | lodash.js  
+544.10 kB  | 71.18 kB   | 72.48 kB   | 25.85 kB   | 26.20 kB   |          2 | lodash.js  
 
-555.77 kB  | 270.85 kB  | 270.13 kB  | 88.23 kB   | 90.80 kB   |          2 | d3.js      
+555.77 kB  | 270.81 kB  | 270.13 kB  | 88.21 kB   | 90.80 kB   |          2 | d3.js      
 
-1.01 MB    | 439.88 kB  | 458.89 kB  | 122.24 kB  | 126.71 kB  |          3 | bundle.min.js 
+1.01 MB    | 439.64 kB  | 458.89 kB  | 122.16 kB  | 126.71 kB  |          2 | bundle.min.js 
 
-1.25 MB    | 646.86 kB  | 646.76 kB  | 160.24 kB  | 163.73 kB  |          2 | three.js   
+1.25 MB    | 645.80 kB  | 646.76 kB  | 159.59 kB  | 163.73 kB  |          2 | three.js   
 
-2.14 MB    | 714.65 kB  | 724.14 kB  | 161.41 kB  | 181.07 kB  |          2 | victory.js 
+2.14 MB    | 714.13 kB  | 724.14 kB  | 161.16 kB  | 181.07 kB  |          2 | victory.js 
 
-3.20 MB    | 1.01 MB    | 1.01 MB    | 323.86 kB  | 331.56 kB  |          3 | echarts.js 
+3.20 MB    | 1.00 MB    | 1.01 MB    | 323.35 kB  | 331.56 kB  |          3 | echarts.js 
 
-6.69 MB    | 2.23 MB    | 2.31 MB    | 460.69 kB  | 488.28 kB  |          4 | antd.js    
+6.69 MB    | 2.23 MB    | 2.31 MB    | 460.30 kB  | 488.28 kB  |          4 | antd.js    
 
-10.95 MB   | 3.34 MB    | 3.49 MB    | 856.46 kB  | 915.50 kB  |          4 | typescript.js 
+10.95 MB   | 3.34 MB    | 3.49 MB    | 855.59 kB  | 915.50 kB  |          4 | typescript.js