Converting React Component to Typescript?

Question

I'm trying to copy the example of React+Redux component to typescript: https://medium.com/@stowball/a-dummys-guide-to-redux-and-thunk-in-react-d8904a7005d3

I'm hitting a deadend with the function:

export default connect(mapStateToProps, mapDispatchToProps)(ItemList);

I'm getting an error about how it's not mappable to ItemList.

One way around this I believe is to change the class declaration to:

class ItemList extends React.Component<{proper component map}, {proper state map}> {

However if I do this because the props have now been mapped I cannot simply include ItemList as and am now expected to provide the params.

Another option might be to: (props as any).fetchData() however this feels wrong.

Is there a way around this? Am I doing React+Redux wrong in typescript?

Why it's a problem to provide the params which are needed by the component? — NoNameProvided
Because then I can't just use <ItemList /> and have to provide params while in the javascript example I don't have to do that. — meds

NoNameProvided NoNameProvided · Accepted Answer · 2017-09-13T11:07:52

After you create everything, you export it together with connect.

interface PassedProps {
  productId: number;
}

interface StateToProps {
  addedProductIds: number[];
  quantityById: { [key: string]: number };
  quantity: number;
}

interface DispatchToProps {
  addToCart: (productId: number) => void;
  removeFromCart: (productId: number) => void;
}

// Needs to be added to src/store:GlobalStore interface with the correct prop name created from the name of the reducer
export interface CartState {
  addedProductIds: number[];
  quantityById: { [key: string]: number };
}

const mapStateToProps = (globalState: GlobalState): StateToProps => {
  const state: CartState = globalState.cart;

  return {
    addedProductIds: state.addedProductIds,
    quantityById: state.quantityById,
    quantity: Object.keys(state.quantityById).reduce( (sum: number, key: string) => state.quantityById[key] + sum, 0)
  };
};


const mapDispatchToProps = (dispatch: Dispatch<any>): DispatchToProps => {
  return {
    addToCart: (productId: number) => dispatch({ type: 'ADD_TO_CART', productId } as AddToCartAction),
    removeFromCart: (productId: number) => dispatch({ type: 'REMOVE_FROM_CART', productId } as RemoveFromCartAction),
  };
}

export type Props = PassedProps & StateToProps & DispatchToProps;

class CartButton extends Component<Props, CartState> {
  render() {
    const { quantity } = this.props;

    return (
      <View>
        <Text>
          { this.props.addedProductIds.length } type item is in the cart, totals to { quantity } item.
        </Text>
        <View>
          <Button
            onPress={this.onPressAdd.bind(this)}
            title="Add to Cart"
            color="#841584"
          />

          <Button
            onPress={this.onPressRemove.bind(this)}
            title="Removefrom Cart"
            color="#841584"
          />
        </View>
      </View>
    );
  }

  onPressAdd() {
    this.props.addToCart(this.props.productId);
  }

  onPressRemove() {
    this.props.removeFromCart(this.props.productId);
  }
}

export default connect<StateToProps, DispatchToProps, PassedProps>(mapStateToProps, mapDispatchToProps)(CartButton);

Then you can use it with specifying with the required props to be passed (PassedProps interface):

import CartButton from '../components/CartButton';

// ....
  render() {
    return(<CartButton productId={5} />)
  }

Converting React Component to Typescript?

1 Answers