Typescript compile errors with many FormikHelpers when using nested fields

🐛 Bug report

On a project that uses Typescript and nested fields, the defs are not flexible enough for many functions in FormikHelpers.

interface Values {
  some: {
    nested: string;
  };
}

const MyEnhancedForm = withFormik({
  mapPropsToValues: (): Values => ({
    some: { nested: "" }
  }),
  handleSubmit: () => {}
})(props => {
  const { setFieldValue } = props;
  return (
    <form onSubmit={props.handleSubmit}>
      <Field name="some.nested">
        {({ field }: FieldProps<string>) => {
          return (
            <input
              type="text"
              {...field}
              onChange={event =>
                setFieldValue("some.nested", event.target.value)
              }
            />
          );
        }}
      </Field>
      <button type="submit">Submit</button>

      <DisplayFormikState {...props} />
    </form>
  );
});

In the above example, the #setFieldValue() call is invalid bc the function is defined using (field: keyof Values & string, ... Obviously some.nested doesn’t exist as a key of Values, so it doesn’t compile.

Expected behavior

Nested keys should be allowed as a field key in FormikHelpers functions.

Reproducible example

https://codesandbox.io/s/typescript-formikhelpers-defs-dont-work-for-nested-values-9r5nm

Suggested solution(s)

The field key either needs to be relaxed to string or figure out some other Typescript magic to include the nested field names.

Your environment

Software	Version(s)
Formik	2.0.1-rc.12
React	16.8.6
TypeScript	3.5.1
Browser	Chrome 75.0.3770.142 (latest)
npm/Yarn	npm 5.6.0
Operating System	MacOS 10.14.5

[davidroeca]

Still relevant

[davidroeca]

This is still an issue for me.