diff --git a/src/test/utils/getValidJson.spec.ts b/src/test/utils/getValidJson.spec.ts
index a84eb04..1e1f922 100644
--- a/src/test/utils/getValidJson.spec.ts
+++ b/src/test/utils/getValidJson.spec.ts
@@ -33,4 +33,18 @@ describe('jsonValidator', () => {
     }
     expect(test).toThrow(JsonParseArrayError)
   })
+
+  it('should throw an error when null is passed', () => {
+    const test = () => {
+      getValidJson(null as any)
+    }
+    expect(test).toThrow(InvalidJsonError)
+  })
+
+  it('should throw an error when undefined is passed', () => {
+    const test = () => {
+      getValidJson(undefined as any)
+    }
+    expect(test).toThrow(InvalidJsonError)
+  })
 })
diff --git a/src/utils/getValidJson.ts b/src/utils/getValidJson.ts
index 17f9cbb..8d8670b 100644
--- a/src/utils/getValidJson.ts
+++ b/src/utils/getValidJson.ts
@@ -6,6 +6,8 @@ import { JsonParseArrayError, InvalidJsonError } from '../types/errors'
  */
 export const getValidJson = (str: string | object) => {
   try {
+    if (str === null || str === undefined) throw new InvalidJsonError()
+
     if (Array.isArray(str)) throw new JsonParseArrayError()
 
     if (typeof str === 'object') return str