diff --git a/src/lib/utils/typeUtils.test.ts b/src/lib/utils/typeUtils.test.ts
index c957ed15..ab3deae3 100644
--- a/src/lib/utils/typeUtils.test.ts
+++ b/src/lib/utils/typeUtils.test.ts
@@ -87,6 +87,8 @@ describe('typeUtils', () => {
 
   it('valueType', () => {
     strictEqual(valueType(2, JSON), 'number')
+    strictEqual(valueType(-2, JSON), 'number')
+    strictEqual(valueType(2.4e3, JSON), 'number')
     strictEqual(valueType('some text', JSON), 'string')
     strictEqual(valueType(true, JSON), 'boolean')
     strictEqual(valueType(false, JSON), 'boolean')
@@ -96,12 +98,15 @@ describe('typeUtils', () => {
     strictEqual(valueType(123n, JSON), 'number')
     strictEqual(valueType(new Date(), JSON), 'unknown')
     strictEqual(valueType(new LosslessNumber('123'), LosslessJSONParser as JSON), 'number')
+    strictEqual(valueType(new LosslessNumber('2.4e3'), LosslessJSONParser as JSON), 'number')
+    strictEqual(valueType(new LosslessNumber('-4.0'), LosslessJSONParser as JSON), 'number')
   })
 
   it('isStringContainingPrimitiveValue', () => {
     strictEqual(isStringContainingPrimitiveValue(22, JSON), false)
     strictEqual(isStringContainingPrimitiveValue('text', JSON), false)
     strictEqual(isStringContainingPrimitiveValue('2.4', JSON), true)
+    strictEqual(isStringContainingPrimitiveValue('-2.4', JSON), true)
     strictEqual(isStringContainingPrimitiveValue('2e3', JSON), true)
     strictEqual(isStringContainingPrimitiveValue('true', JSON), true)
     strictEqual(isStringContainingPrimitiveValue('false', JSON), true)
diff --git a/src/lib/utils/typeUtils.ts b/src/lib/utils/typeUtils.ts
index e14ff787..90cd66ac 100644
--- a/src/lib/utils/typeUtils.ts
+++ b/src/lib/utils/typeUtils.ts
@@ -1,6 +1,6 @@
 // TODO: unit test typeUtils.js
 
-import { isDigit, isNumber } from './numberUtils.js'
+import { isNumber } from './numberUtils.js'
 import type { JSONParser } from '../types.js'
 
 /**
@@ -118,9 +118,9 @@ export function valueType(value: unknown, parser: JSONParser): string {
     return 'object'
   }
 
-  // unknown type. Try out what stringfying results in
+  // unknown type (like a LosslessNumber). Try out what stringfying results in
   const valueStr = parser.stringify(value)
-  if (valueStr && isDigit(valueStr[0])) {
+  if (valueStr && isNumber(valueStr)) {
     return 'number'
   }
   if (valueStr === 'true' || valueStr === 'false') {