[fix] Handle non-primitives in isNumber

src/helpers/helpers.math.ts

@@ -57,8 +57,15 @@ export function _factorize(value: number) {
   return result;
 }
 
+/**
+ * Verifies that attempting to coerce n to string or number won't throw a TypeError.
+ */
+function isNonPrimitive(n: unknown) {
+  return typeof n === 'symbol' || (typeof n === 'object' && n !== null && !(Symbol.toPrimitive in n || 'toString' in n || 'valueOf' in n));
+}
+
 export function isNumber(n: unknown): n is number {
-  return !isNaN(parseFloat(n as string)) && isFinite(n as number);
+  return !isNonPrimitive(n) && !isNaN(parseFloat(n as string)) && isFinite(n as number);
 }
 
 export function almostWhole(x: number, epsilon: number) {

test/specs/helpers.math.tests.js

@@ -103,6 +103,8 @@ describe('Chart.helpers.math', function() {
     expect(math.isNumber(NaN)).toBe(false);
     expect(math.isNumber(undefined)).toBe(false);
     expect(math.isNumber('cbc')).toBe(false);
+    expect(math.isNumber(Symbol())).toBe(false);
+    expect(math.isNumber(Object.create(null))).toBe(false);
   });
 
   it('should compute shortest distance between angles', function() {