js: avoid NaN and Infinity names inside with

evanw · Oct 18, 2023 · 427ee60 · 427ee60
1 parent f9b4551
commit 427ee60
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Showing 3 changed files with 103 additions and 3 deletions.
diff --git a/internal/bundler_tests/bundler_ts_test.go b/internal/bundler_tests/bundler_ts_test.go
@@ -2890,3 +2890,49 @@ func TestTSExperimentalDecoratorsManglePropsStaticMethods(t *testing.T) {
 		},
 	})
 }
+
+func TestTSPrintNonFiniteNumberInsideWith(t *testing.T) {
+	ts_suite.expectBundled(t, bundled{
+		files: map[string]string{
+			"/entry.ts": `
+				// Use const enums to force inline values
+				const enum Foo {
+					NAN = 0 / 0,
+					POS_INF = 1 / 0,
+					NEG_INF = -1 / 0,
+				}
+
+				//! It's ok to use "NaN" and "Infinity" here
+				console.log(
+					Foo.NAN,
+					Foo.POS_INF,
+					Foo.NEG_INF,
+				)
+				checkPrecedence(
+					1 / Foo.NAN,
+					1 / Foo.POS_INF,
+					1 / Foo.NEG_INF,
+				)
+
+				//! We must not use "NaN" or "Infinity" inside "with"
+				with (x) {
+					console.log(
+						Foo.NAN,
+						Foo.POS_INF,
+						Foo.NEG_INF,
+					)
+					checkPrecedence(
+						1 / Foo.NAN,
+						1 / Foo.POS_INF,
+						1 / Foo.NEG_INF,
+					)
+				}
+			`,
+		},
+		entryPaths: []string{"/entry.ts"},
+		options: config.Options{
+			Mode:          config.ModePassThrough,
+			AbsOutputFile: "/out.js",
+		},
+	})
+}
diff --git a/internal/bundler_tests/snapshots/snapshots_ts.txt b/internal/bundler_tests/snapshots/snapshots_ts.txt
@@ -1753,6 +1753,40 @@ console.log("success");
 // Users/user/project/node_modules/package2/path.js
 console.log("success");
 
+================================================================================
+TestTSPrintNonFiniteNumberInsideWith
+---------- /out.js ----------
+var Foo = /* @__PURE__ */ ((Foo2) => {
+  Foo2[Foo2["NAN"] = NaN] = "NAN";
+  Foo2[Foo2["POS_INF"] = Infinity] = "POS_INF";
+  Foo2[Foo2["NEG_INF"] = -Infinity] = "NEG_INF";
+  return Foo2;
+})(Foo || {});
+//! It's ok to use "NaN" and "Infinity" here
+console.log(
+  NaN /* NAN */,
+  Infinity /* POS_INF */,
+  -Infinity /* NEG_INF */
+);
+checkPrecedence(
+  1 / NaN /* NAN */,
+  1 / Infinity /* POS_INF */,
+  1 / -Infinity /* NEG_INF */
+);
+//! We must not use "NaN" or "Infinity" inside "with"
+with (x) {
+  console.log(
+    0 / 0 /* NAN */,
+    1 / 0 /* POS_INF */,
+    -1 / 0 /* NEG_INF */
+  );
+  checkPrecedence(
+    1 / (0 / 0) /* NAN */,
+    1 / (1 / 0) /* POS_INF */,
+    1 / (-1 / 0) /* NEG_INF */
+  );
+}
+
 ================================================================================
 TestTSSiblingEnum
 ---------- /out/number.js ----------

diff --git a/internal/js_printer/js_printer.go b/internal/js_printer/js_printer.go
@@ -367,6 +367,7 @@ type printer struct {
 	arrowExprStart     int
 	forOfInitStart     int
 
+	withNesting          int
 	prevOpEnd            int
 	needSpaceBeforeDot   int
 	prevRegExpEnd        int
@@ -549,9 +550,26 @@ func (p *printer) printNumber(value float64, level js_ast.L) {
 
 	if value != value {
 		p.printSpaceBeforeIdentifier()
-		p.print("NaN")
+		if p.withNesting != 0 {
+			// "with (x) NaN" really means "x.NaN" so avoid identifiers when "with" is present
+			wrap := level >= js_ast.LMultiply
+			if wrap {
+				p.print("(")
+			}
+			if p.options.MinifyWhitespace {
+				p.print("0/0")
+			} else {
+				p.print("0 / 0")
+			}
+			if wrap {
+				p.print(")")
+			}
+		} else {
+			p.print("NaN")
+		}
 	} else if value == positiveInfinity || value == negativeInfinity {
-		wrap := (p.options.MinifySyntax && level >= js_ast.LMultiply) ||
+		// "with (x) Infinity" really means "x.Infinity" so avoid identifiers when "with" is present
+		wrap := ((p.options.MinifySyntax || p.withNesting != 0) && level >= js_ast.LMultiply) ||
 			(value == negativeInfinity && level >= js_ast.LPrefix)
 		if wrap {
 			p.print("(")
@@ -562,7 +580,7 @@ func (p *printer) printNumber(value float64, level js_ast.L) {
 		} else {
 			p.printSpaceBeforeIdentifier()
 		}
-		if !p.options.MinifySyntax {
+		if !p.options.MinifySyntax && p.withNesting == 0 {
 			p.print("Infinity")
 		} else if p.options.MinifyWhitespace {
 			p.print("1/0")
@@ -4417,7 +4435,9 @@ func (p *printer) printStmt(stmt js_ast.Stmt, flags printStmtFlags) {
 			p.printExpr(s.Value, js_ast.LLowest, 0)
 		}
 		p.print(")")
+		p.withNesting++
 		p.printBody(s.Body)
+		p.withNesting--
 
 	case *js_ast.SLabel:
 		// Avoid printing a source mapping that masks the one from the label