fix(es/minifier): Don't ignore nullish coalescing (#6272)

crates/swc/tests/tsc-references/logicalAssignment1(target=es2020).2.minified.js

@@ -1,2 +1,2 @@
 //// [logicalAssignment1.ts]
-a && (a = "foo"), b || (b = "foo"), c = "foo", d && (d = 42), e || (e = 42), f = 42, g && (g = 42), h || (h = 42), i = 42;
+a && (a = "foo"), b || (b = "foo"), c ?? (c = "foo"), d && (d = 42), e || (e = 42), f ?? (f = 42), g && (g = 42), h || (h = 42), i ?? (i = 42);

crates/swc/tests/tsc-references/logicalAssignment10(target=es2020).2.minified.js

@@ -1,5 +1,5 @@
 //// [logicalAssignment10.ts]
 var _obj, _ref, _ref1, _ref2, count = 0, obj = {};
-(_obj = obj)[_ref = ++count], _obj[_ref] = ++count, (_ref1 = ({
+(_obj = obj)[_ref = ++count] ?? (_obj[_ref] = ++count), (_ref1 = ({
     obj
-}).obj)[_ref2 = ++count], _ref1[_ref2] = ++count;
+}).obj)[_ref2 = ++count] ?? (_ref1[_ref2] = ++count);

crates/swc/tests/tsc-references/logicalAssignment11(target=es2020).2.minified.js

@@ -1,3 +1,3 @@
 //// [logicalAssignment11.ts]
-let x;
-(x ?? "x").length, (x ?? "x").length;
+let x, d, e;
+d ?? (d = x ?? "x"), d.length, e ?? (e = x ?? "x"), e.length;

crates/swc/tests/tsc-references/logicalAssignment11(target=es2022).2.minified.js

@@ -1,3 +1,3 @@
 //// [logicalAssignment11.ts]
-let x, e;
-(x ?? "x").length, (e ??= x ?? "x").length;
+let x, d, e;
+d ?? (d = x ?? "x"), d.length, (e ??= x ?? "x").length;

crates/swc/tests/tsc-references/logicalAssignment3(target=es2020).2.minified.js

@@ -1,3 +1,3 @@
 //// [logicalAssignment3.ts]
 var _a, _b, _c;
-(_a = a).baz && (_a.baz = result.baz), (_b = b).baz || (_b.baz = result.baz), (_c = c).baz, _c.baz = result.baz;
+(_a = a).baz && (_a.baz = result.baz), (_b = b).baz || (_b.baz = result.baz), (_c = c).baz ?? (_c.baz = result.baz);

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

@@ -683,10 +683,7 @@ where
         match e {
             Expr::Lit(..) | Expr::Ident(..) => true,
 
-            Expr::Bin(BinExpr {
-                op: op!("&&") | op!("||") | op!("??"),
-                ..
-            }) => false,
+            Expr::Bin(BinExpr { op, .. }) if op.may_short_circuit() => false,
 
             Expr::Bin(e) => {
                 self.is_return_arg_simple_enough_for_iife_eval(&e.left)

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

@@ -664,11 +664,8 @@ where
             Expr::Paren(e) => return self.ignore_return_value(&mut e.expr),
 
             Expr::Bin(BinExpr {
-                op: op!("&&") | op!("||"),
-                left,
-                right,
-                ..
-            }) => {
+                op, left, right, ..
+            }) if op.may_short_circuit() => {
                 let ctx = Ctx {
                     dont_use_negated_iife: self.ctx.dont_use_negated_iife
                         || self.options.side_effects,
@@ -1472,7 +1469,7 @@ where
     fn visit_mut_bin_expr(&mut self, n: &mut BinExpr) {
         {
             let ctx = Ctx {
-                in_cond: self.ctx.in_cond || matches!(n.op, op!("&&") | op!("||") | op!("??")),
+                in_cond: self.ctx.in_cond || n.op.may_short_circuit(),
                 ..self.ctx
             };
 

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

@@ -84,7 +84,7 @@ where
     pub(super) fn remove_bin_paren(&mut self, n: &mut BinExpr) {
         if let Expr::Bin(right) = &mut *n.right {
             if right.op == n.op {
-                if matches!(n.op, op!("&&") | op!("||") | op!("??"))
+                if n.op.may_short_circuit()
                     || (right.left.is_str() && right.op == op!(bin, "+"))
                     || (n.left.is_str() && right.right.is_str())
                 {

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

@@ -1570,9 +1570,8 @@ where
                     return Ok(false);
                 }
 
-                match *op {
-                    op!("&&") | op!("||") | op!("??") => return Ok(false),
-                    _ => {}
+                if op.may_short_circuit() {
+                    return Ok(false);
                 }
 
                 trace_op!("seq: Try right of bin");

crates/swc_ecma_minifier/tests/fixture/pr/6272/input.js

@@ -0,0 +1 @@
+a ?? (a = b);

crates/swc_ecma_minifier/tests/fixture/pr/6272/output.js

@@ -0,0 +1 @@
+a ?? (a = b);