> For the complete documentation index, see [llms.txt](https://ploegert.gitbook.io/til/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://ploegert.gitbook.io/til/programmy/react/formiks-validation-schema-as-a-function.md).

# Formik's Validation Schema As A Function

The most straightforward way to use [Formik](https://jaredpalmer.com/formik)'s `validationSchema` is to provide it with a [Yup](https://github.com/jquense/yup) object defining your form's validations.

```javascript
const MyComponent = withFormik({
  // ...

  validationSchema: yup.object().shape({
    email: yup.string().required(),
    feedback: yup.string().required(),
  }),
  
  // ...
})(MyForm);
```

There may be a point at which you need access to the `props` being passed to `MyComponent` in order to construct the proper set of validations. Formik supports this by allowing `validationSchema` to be a function.

```javascript
const MyComponent = withFormik({
  // ...

  validationSchema: (props) => {
    let emailSchema;
    if(props.allowAnonymous) {
      emailSchema = yup.string();
    } else {
      emailSchema = yup.string().required();
    }

    return yup.object().shape({
      email: emailSchema,
      feedback: yup.string().required(),
    });
  },
  
  // ...
})(MyForm);
```

When `validationSchema` is a function, its first argument is the set of props passed to that component.


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