Fix getIn unexpected value

.changeset/kind-poems-kick.md

@@ -0,0 +1,5 @@
+---
+'formik': patch
+---
+
+Changed `getIn` to return undefined when it can't find a value AND a parent of that value is "falsy" ( "" / 0 / null / false )

packages/formik/src/utils.ts

@@ -76,6 +76,12 @@ export function getIn(
   while (obj && p < path.length) {
     obj = obj[path[p++]];
   }
+
+  // check if path is not in the end
+  if (p !== path.length && !obj) {
+    return def;
+  }
+
   return obj === undefined ? def : obj;
 }
 

packages/formik/test/utils.test.tsx

@@ -152,7 +152,11 @@ describe('utils', () => {
     const obj = {
       a: {
         b: 2,
+        c: false,
+        d: null,
       },
+      t: true,
+      s: 'a random string',
     };
 
     it('gets a value by array path', () => {
@@ -166,6 +170,22 @@ describe('utils', () => {
     it('return "undefined" if value was not found using given path', () => {
       expect(getIn(obj, 'a.z')).toBeUndefined();
     });
+
+    it('return "undefined" if value was not found using given path and an intermediate value is "false"', () => {
+      expect(getIn(obj, 'a.c.z')).toBeUndefined();
+    });
+
+    it('return "undefined" if value was not found using given path and an intermediate value is "null"', () => {
+      expect(getIn(obj, 'a.d.z')).toBeUndefined();
+    });
+
+    it('return "undefined" if value was not found using given path and an intermediate value is "true"', () => {
+      expect(getIn(obj, 't.z')).toBeUndefined();
+    });
+
+    it('return "undefined" if value was not found using given path and an intermediate value is a string', () => {
+      expect(getIn(obj, 's.z')).toBeUndefined();
+    });
   });
 
   describe('setIn', () => {