fix(es/minifier): Fix handling of .toFixed call without an argument (#5868)

crates/swc_ecma_minifier/src/compress/pure/evaluate.rs

@@ -282,7 +282,12 @@ impl Pure<'_> {
         }
 
         if &*method.sym == "toFixed" {
-            if let Some(precision) = eval_as_number(&self.expr_ctx, &args[0].expr) {
+            if let Some(precision) = args
+                .first()
+                // https://tc39.es/ecma262/multipage/numbers-and-dates.html#sec-number.prototype.tofixed
+                // 3. Assert: If fractionDigits is undefined, then f is 0.
+                .map_or(Some(0f64), |arg| eval_as_number(&self.expr_ctx, &arg.expr))
+            {
                 let precision = precision.floor() as usize;
                 let value = num_to_fixed(num.value, precision + 1);
 

crates/swc_ecma_minifier/tests/fixture/issues/5864/analysis-snapshot.rust-debug

@@ -0,0 +1,42 @@
+TestSnapshot {
+    vars: [
+        (
+            (
+                Atom('foo' type=inline),
+                #1,
+            ),
+            VarUsageInfo {
+                inline_prevented: false,
+                ref_count: 1,
+                cond_init: false,
+                declared: false,
+                declared_count: 0,
+                declared_as_fn_param: false,
+                declared_as_fn_expr: false,
+                assign_count: 0,
+                mutation_by_call_count: 0,
+                usage_count: 0,
+                reassigned_with_assignment: false,
+                reassigned_with_var_decl: false,
+                mutated: true,
+                has_property_access: false,
+                has_property_mutation: false,
+                accessed_props: {},
+                exported: false,
+                used_above_decl: true,
+                is_fn_local: true,
+                used_by_nested_fn: false,
+                executed_multiple_time: false,
+                used_in_cond: false,
+                var_kind: None,
+                var_initialized: true,
+                declared_as_catch_param: false,
+                no_side_effect_for_member_access: false,
+                used_as_callee: false,
+                used_as_arg: false,
+                pure_fn: false,
+                infects: [],
+            },
+        ),
+    ],
+}

crates/swc_ecma_minifier/tests/fixture/issues/5864/config.json

@@ -0,0 +1,46 @@
+{
+    "arguments": false,
+    "arrows": true,
+    "booleans": true,
+    "booleans_as_integers": false,
+    "collapse_vars": true,
+    "comparisons": true,
+    "computed_props": true,
+    "conditionals": true,
+    "dead_code": true,
+    "directives": true,
+    "drop_console": false,
+    "drop_debugger": true,
+    "evaluate": true,
+    "expression": false,
+    "hoist_funs": false,
+    "hoist_props": true,
+    "hoist_vars": false,
+    "if_return": true,
+    "join_vars": true,
+    "keep_classnames": false,
+    "keep_fargs": true,
+    "keep_fnames": false,
+    "keep_infinity": false,
+    "loops": true,
+    "negate_iife": true,
+    "properties": true,
+    "reduce_funcs": false,
+    "reduce_vars": false,
+    "side_effects": true,
+    "switches": true,
+    "typeofs": true,
+    "unsafe": false,
+    "unsafe_arrows": false,
+    "unsafe_comps": false,
+    "unsafe_Function": false,
+    "unsafe_math": false,
+    "unsafe_symbols": false,
+    "unsafe_methods": false,
+    "unsafe_proto": false,
+    "unsafe_regexp": false,
+    "unsafe_undefined": false,
+    "unused": true,
+    "const_to_let": true,
+    "pristine_globals": true
+}

crates/swc_ecma_minifier/tests/fixture/issues/5864/input.js

@@ -0,0 +1,3 @@
+foo = {
+    v: (0).toFixed(),
+};

crates/swc_ecma_minifier/tests/fixture/issues/5864/output.js

@@ -0,0 +1,3 @@
+foo = {
+    v: "0"
+};

crates/swc_ecma_minifier/tests/fixture/issues/5864/output.mangleOnly.js

@@ -0,0 +1,3 @@
+foo = {
+    v: (0).toFixed()
+};