feat: detect Symbol() and BigInt() in no-constant-binary-expression (#20981)

kimtaejin3 · web-flow · commit b1f910628e29 · 2026-06-24T23:46:40.000+02:00
diff --git a/lib/rules/no-constant-binary-expression.js b/lib/rules/no-constant-binary-expression.js
@@ -89,7 +89,9 @@ function hasConstantNullishness(scope, node, nonNullish) {
 			return (
 				(functionName === "Boolean" ||
 					functionName === "String" ||
-					functionName === "Number") &&
+					functionName === "Number" ||
+					functionName === "Symbol" ||
+					functionName === "BigInt") &&
 				isReferenceToGlobalVariable(scope, node.callee)
 			);
 		}
@@ -374,7 +376,10 @@ function hasConstantStrictBooleanComparison(scope, node) {
 			const functionName = node.callee.name;
 
 			if (
-				(functionName === "String" || functionName === "Number") &&
+				(functionName === "String" ||
+					functionName === "Number" ||
+					functionName === "BigInt" ||
+					functionName === "Symbol") &&
 				isReferenceToGlobalVariable(scope, node.callee)
 			) {
 				return true;
diff --git a/tests/lib/rules/no-constant-binary-expression.js b/tests/lib/rules/no-constant-binary-expression.js
@@ -55,6 +55,8 @@ ruleTester.run("no-constant-binary-expression", rule, {
 		"function Boolean(n) { return n; }; Boolean(x) ?? foo",
 		"function String(n) { return n; }; String(x) ?? foo",
 		"function Number(n) { return n; }; Number(x) ?? foo",
+		"function Symbol(n) { return n; }; Symbol(x) ?? foo",
+		"function BigInt(n) { return n; }; BigInt(x) ?? foo",
 		"function Boolean(n) { return Math.random(); }; Boolean(x) === 1",
 		"function Boolean(n) { return Math.random(); }; Boolean(1) == true",
 
@@ -894,6 +896,24 @@ ruleTester.run("no-constant-binary-expression", rule, {
 				},
 			],
 		},
+		{
+			code: "Symbol(x) ?? foo",
+			errors: [
+				{
+					messageId: "constantShortCircuit",
+					data: { property: "nullishness", operator: "??" },
+				},
+			],
+		},
+		{
+			code: "BigInt(x) ?? foo",
+			errors: [
+				{
+					messageId: "constantShortCircuit",
+					data: { property: "nullishness", operator: "??" },
+				},
+			],
+		},
 
 		// Binary expression with comparison to null
 		{
@@ -941,6 +961,42 @@ ruleTester.run("no-constant-binary-expression", rule, {
 				},
 			],
 		},
+		{
+			code: "Symbol(x) != null",
+			errors: [
+				{
+					messageId: "constantBinaryOperand",
+					data: { otherSide: "right", operator: "!=" },
+				},
+			],
+		},
+		{
+			code: "Symbol(x) != undefined",
+			errors: [
+				{
+					messageId: "constantBinaryOperand",
+					data: { otherSide: "right", operator: "!=" },
+				},
+			],
+		},
+		{
+			code: "BigInt(x) != null",
+			errors: [
+				{
+					messageId: "constantBinaryOperand",
+					data: { otherSide: "right", operator: "!=" },
+				},
+			],
+		},
+		{
+			code: "BigInt(x) != undefined",
+			errors: [
+				{
+					messageId: "constantBinaryOperand",
+					data: { otherSide: "right", operator: "!=" },
+				},
+			],
+		},
 
 		// Binary expression with loose comparison to boolean
 		{
@@ -1476,6 +1532,24 @@ ruleTester.run("no-constant-binary-expression", rule, {
 				},
 			],
 		},
+		{
+			code: "true === Symbol(x)",
+			errors: [
+				{
+					messageId: "constantBinaryOperand",
+					data: { otherSide: "left", operator: "===" },
+				},
+			],
+		},
+		{
+			code: "true === BigInt(x)",
+			errors: [
+				{
+					messageId: "constantBinaryOperand",
+					data: { otherSide: "left", operator: "===" },
+				},
+			],
+		},
 		{
 			code: "Boolean(0) == !({})",
 			errors: [
@@ -1721,6 +1795,24 @@ ruleTester.run("no-constant-binary-expression", rule, {
 				},
 			],
 		},
+		{
+			code: "Symbol(x) === null",
+			errors: [
+				{
+					messageId: "constantBinaryOperand",
+					data: { otherSide: "right", operator: "===" },
+				},
+			],
+		},
+		{
+			code: "BigInt(x) === null",
+			errors: [
+				{
+					messageId: "constantBinaryOperand",
+					data: { otherSide: "right", operator: "===" },
+				},
+			],
+		},
 
 		// Binary expression with strict comparison to undefined
 		{
@@ -1957,6 +2049,24 @@ ruleTester.run("no-constant-binary-expression", rule, {
 				},
 			],
 		},
+		{
+			code: "Symbol(x) === undefined",
+			errors: [
+				{
+					messageId: "constantBinaryOperand",
+					data: { otherSide: "right", operator: "===" },
+				},
+			],
+		},
+		{
+			code: "BigInt(x) === undefined",
+			errors: [
+				{
+					messageId: "constantBinaryOperand",
+					data: { otherSide: "right", operator: "===" },
+				},
+			],
+		},
 
 		/*
 		 * If both sides are newly constructed objects, we can tell they will
