Typing redux forms v7 with TypeScript and React

Question

I've got a plain react-redux-powered form. I wish for there to be a form.container.tsx and a form.component.tsx, where form.container.tsx holds all the connections to redux state minus the Field's. I'm trying to wrap my container in react-redux's connect and then wrapping reduxForm within it to look something like TypeScript, redux-form and connect:

(ideal) form.container.tsx:

interface DummyFormContainerProps {}

export const DummyFormContainer: React.SFC<DummyFormContainerProps> = props => {
  const submitForm = (formValues: object) => {
    alert(formValues);
  };
  return (
    <DummyForm
      onSubmit={submitForm}
    />
  );
};

const mapStateToProps = (state: State) => ({});
const mapDispatchToProps = (dispatch: object) => {
  return {};
};
const mergeProps = (stateProps: State, dispatchProps: object | null, ownProps: object | void) => 
  Object.assign({}, stateProps, dispatchProps, ownProps);

const formConfiguration = {
  form: 'dummy-form',
  forceUnregisterOnUnmount: true
};

export default connect(mapStateToProps, mapDispatchToProps)(
  reduxForm(formConfiguration)(DummyFormContainer)
);

The above does not work, but if I take out the reduxForm() part, I'm left with a working container with no reduxForm Integration:

(working without reduxForm) form.container.tsx:

export default connect(mapStateToProps, mapDispatchToProps, mergeProps)(
  DummyFormContainer
);

And I've tried different variations with reduxForms and connect, all not currently working:

(with classes) form.container.tsx:

export class DummyFormContainer extends React.Component<DummyFormContainerProps, void> {
  submitForm = (formValues: object) => {
    alert(formValues);
  }

  render() {
    return (
      <DummyForm
        onSubmit={this.submitForm}
      />
    );
  }
}

const mapStateToProps = (state: State) => ({});
const mapDispatchToProps = (dispatch: object) => {
  return {};
};
const mergeProps = (stateProps: State, dispatchProps: object | null, ownProps: object | void) => 
  Object.assign({}, stateProps, dispatchProps, ownProps);

const formConfiguration = {
  form: 'business-registration',
};

export default connect(mapStateToProps, mapDispatchToProps, mergeProps)(
  reduxForm(formConfiguration)(DummyFormContainer) // ERROR
);

error:

./src/modules/dummy-form/dummy-form.container.tsx
(100,32): error TS2345: Argument of type 'typeof DummyFormContainer' is not assignable to parameter of type 'ComponentType<InjectedFormProps<{}, {}>>'.
  Type 'typeof DummyFormContainer' is not assignable to type 'StatelessComponent<InjectedFormProps<{}, {}>>'.
    Type 'typeof DummyFormContainer' provides no match for the signature '(props: InjectedFormProps<{}, {}> & { children?: ReactNode; }, context?: any): ReactElement<any> | null'.

(with stateless functional components) form.container.tsx:

export const DummyFormContainer: React.SFC<DummyFormContainerProps> = props => {
  const submitForm = (formValues: object) => {
    alert(formValues);
  };
  return (
    <DummyForm
      onSubmit={submitForm}
    />
  );
};

export default connect(mapStateToProps, mapDispatchToProps, mergeProps)(
  reduxForm(formConfiguration)(DummyFormContainer) // ERROR
);

error:

./src/modules/dummy-form/dummy-form.container.tsx
(100,3): error TS2345: Argument of type 'DecoratedComponentClass<{}, Partial<ConfigProps<{}, {}>>>' is not assignable to parameter of type 'ComponentType<(State & null & void) | (State & null & object) | (State & object & void) | (State ...'.
  Type 'DecoratedComponentClass<{}, Partial<ConfigProps<{}, {}>>>' is not assignable to type 'StatelessComponent<(State & null & void) | (State & null & object) | (State & object & void) | (S...'.
    Type 'DecoratedComponentClass<{}, Partial<ConfigProps<{}, {}>>>' provides no match for the signature '(props: (State & null & void & { children?: ReactNode; }) | (State & null & object & { children?: ReactNode; }) | (State & object & void & { children?: ReactNode; }) | (State & object & { children?: ReactNode; }), context?: any): ReactElement<any> | null'.

The form.component.tsx looks like this:

import * as React from 'react';
import Input from '../../components/input';

interface DummyFormProps {
  onSubmit: (formValues: object) => void
}

export const DummyForm: React.SFC<DummyFormProps> = () => {
  return (
    <div>
      <h1>DummyForm (no state)</h1>
      <form>
        <Input inputType="primary" />
      </form>
    </div>
  );
};

export default DummyForm;

And the < Input > component is a regular React component.

Does anyone know how to properly connect reduxForm and react-redux's connect()?

Answer 1

Here's a fully typed example that allows initializing a form using initialValues and passing additional props (as IOwnProps):

sampleForm.tsx:

export interface IFormData {
  userId: string;
}

export interface IOwnProps {
  foo: string;
}

export interface IDispatchProps {
  onSubmit: (data: IFormData, dispatch: Dispatch<any>, props: IOwnProps) => void;
}

type AllSampleFormProps = IOwnProps & IDispatchProps & InjectedFormProps<IFormData, IOwnProps>;

const SampleForm: React.SFC<AllSampleFormProps> = (props) => (
  <form onSubmit={props.handleSubmit(props.onSubmit)}>
    <div>foo={props.foo}</div>
    <Field name="userId" component="input" />
    <button type="submit">Submit</button>
  </form>
);

export const DecoratedSampleForm = reduxForm<IFormData, IOwnProps>({})(SampleForm);

sampleForm.ts:

The trick here is to specify proper return type for mapStateToProps, otherwise compiler will be complaining like other authors pointed out.

function mapStateToProps(state: AppState, props: IOwnProps): ConfigProps<IFormData, IOwnProps> {
  return {
    form: "sampleForm", // Form will be handled by Redux Form using this key
    initialValues: {
      userId: state.somethere.userId // Can also be calculated using props
    }
  }
}

function mapDispatchToProps(dispatch: Dispatch<any>): IDispatchProps {
  return {
    onSubmit: (formData: IFormData, dispatch: Dispatch<any>, props: IOwnProps) => {
      console.log(formData);
      console.log(props);
    }
  }
}

export default connect<ConfigProps<IFormData, IOwnProps>>(
  mapStateToProps,
  mapDispatchToProps
)(DecoratedSampleForm);

Now this form can be mounted like this:

<FormContainer foo="bar"/>

Answer 2

I found that I was able to dismiss the error by providing the connect statement with empty TStateProps and TDispatchProps objects.

interface SampleFormData {
  username: string;
}

interface SampleFormProps {
  saveData: (data: SampleFormData) => void;
}

type AllSampleFormProps = SampleFormProps & InjectedFormProps<SampleFormData>;

const SampleForm: React.SFC<AllSampleFormProps> = (props) => (
  <form onSubmit={props.handleSubmit(props.saveData)}>
    <Field name="username" component="input" />
  </form>
);

const DecoratedSampleForm = reduxForm<SampleFormData>({ form: "sampleForm" })(SampleForm);

export default connect<{},{}>(
  () => ({}),
  (dispatch) => ({
    saveData: (data: SampleFormData) => dispatch({ type: "SAVE_DATA", data })
  })
)(DecoratedSampleForm);

The one downside to this is that it forces us to blindly supply connect props but I felt that this was a more elegant solution than writing an override @types declaration.

To address this shortcoming, I was able to validate the types by providing connect with the correct interfaces versus empty objects; however, this method can only be done temporarily to check the bindings as it doesn't resolve the DecoratedComponentClass error.

export default connect<{}, SampleFormProps, InjectedFormProps<SampleFormData>>(
  () => ({}),
  (dispatch) => ({
    saveData: (data: SampleFormData) => dispatch({ type: "SAVE_DATA", data })
  })
)(DecoratedSampleForm);