fix(types): setFieldValue returns a promise resolving to nothing or a…

…n error object (#3792)

Closes #2384 
Closes #3689

.changeset/metal-apples-remain.md

@@ -0,0 +1,5 @@
+---
+'formik': patch
+---
+
+Update the type for `setFieldValue` to reflect the returned `Promise` and potential returned error(s).

docs/api/formik.md

@@ -191,11 +191,13 @@ Trigger a form submission. The promise will be rejected if form is invalid.
 Number of times user tried to submit the form. Increases when [`handleSubmit`](#handlesubmit-e-reactformevent-htmlformelement-void) is called, resets after calling
 [`handleReset`](#handlereset-void). `submitCount` is readonly computed property and should not be mutated directly.
 
-#### `setFieldValue: (field: string, value: any, shouldValidate?: boolean) => void`
+#### `setFieldValue: (field: string, value: any, shouldValidate?: boolean) => Promise<void | FormikErrors>`
 
 Set the value of a field imperatively. `field` should match the key of
 `values` you wish to update. Useful for creating custom input change handlers. Calling this will trigger validation to run if `validateOnChange` is set to `true` (which it is by default). You can also explicitly prevent/skip validation by passing a third argument as `false`.
 
+If `validateOnChange` is set to `true` and there are errors, they will be resolved in the returned `Promise`.
+
 #### `setStatus: (status?: any) => void`
 
 Set a top-level `status` to anything you want imperatively. Useful for

packages/formik/src/types.tsx

@@ -92,7 +92,11 @@ export interface FormikHelpers<Values> {
     shouldValidate?: boolean
   ) => void;
   /** Set value of form field directly */
-  setFieldValue: (field: string, value: any, shouldValidate?: boolean) => void;
+  setFieldValue(
+    field: string,
+    value: any,
+    shouldValidate?: boolean
+  ): Promise<void | FormikErrors<Values>>;
   /** Set error message of a form field directly */
   setFieldError: (field: string, message: string | undefined) => void;
   /** Set whether field has been touched directly */