Definition of Redux store state object

Question

Definition of Redux store state object

Recently, I started using Typescript in a React/Redux project, and I am facing some confusion regarding how type definitions should be incorporated into the application state. My goal is to make a specific piece of state accessible to a container component through the use of mapStateToProps. However, when attempting to do so, I encounter an error indicating that 'state' requires a type definition.

function mapStateToProps (state) {
  return {
    deals: state.deals
  };
}

javascript typescript redux

Answer 1

Answer №1

To begin, you should establish an interface that encapsulates the entire state of the application:

interface ApplicationState {
    someProp1: {
        someProp1a: string;
        someProp1b: number;
    };
    someProp2: {
        someProp1a: string;
        someProp1b: number;
    };
}

Subsequently, create individual interfaces to represent the state of each smart component (which is a component connected to the store through mapStateToProps):

interface SomeComponentState {
    someProp1: {
        someProp1a: string;
        someProp1b: number;
    };
}

The MyComponentState interface needs to be a subset of AppState, allowing for this type of definition:

type SomeComponentProps = Pick<ApplicationState, "someProp1">;

Furthermore, define a type to represent the actions specific to the smart component:

const actionsCreators = {
    doSomething: (txt: string) => ({ type: "DO_SOMETHING", payload: txt })
};

type SomeComponentActions = { actions: typeof actionsCreators };

The properties of the smart component consist of both its properties and its actions, combined into

SomeComponentProps & SomeComponentActions

.

class MyComponent extends React.Component<SomeComponentProps & SomeComponentActions, void> {
    public render() {
        return <div onClick={() => this.props.actions.doSomething(this.props.someProp1.someProp1a)} >Click me!</div>;
    }
}

You will need to map from the application state to the component state:

function mapStateToProps(state: ApplicationState): SomeComponentProps {
    return {
        someProp1: state.someProp1
    };
}

function mapDispatchToProps(dispatch: Redux.Dispatch<typeof actionsCreators>) {
    return { actions : bindActionCreators(actionsCreators, dispatch) };
}

const MySmarthComponent = connect(mapStateToProps, mapDispatchToProps)(MyComponent);

Answer 2

To begin, you should establish an interface that encapsulates the entire state of the application:

interface ApplicationState {
    someProp1: {
        someProp1a: string;
        someProp1b: number;
    };
    someProp2: {
        someProp1a: string;
        someProp1b: number;
    };
}

Subsequently, create individual interfaces to represent the state of each smart component (which is a component connected to the store through mapStateToProps):

interface SomeComponentState {
    someProp1: {
        someProp1a: string;
        someProp1b: number;
    };
}

The MyComponentState interface needs to be a subset of AppState, allowing for this type of definition:

type SomeComponentProps = Pick<ApplicationState, "someProp1">;

Furthermore, define a type to represent the actions specific to the smart component:

const actionsCreators = {
    doSomething: (txt: string) => ({ type: "DO_SOMETHING", payload: txt })
};

type SomeComponentActions = { actions: typeof actionsCreators };

The properties of the smart component consist of both its properties and its actions, combined into

SomeComponentProps & SomeComponentActions

.

class MyComponent extends React.Component<SomeComponentProps & SomeComponentActions, void> {
    public render() {
        return <div onClick={() => this.props.actions.doSomething(this.props.someProp1.someProp1a)} >Click me!</div>;
    }
}

You will need to map from the application state to the component state:

function mapStateToProps(state: ApplicationState): SomeComponentProps {
    return {
        someProp1: state.someProp1
    };
}

function mapDispatchToProps(dispatch: Redux.Dispatch<typeof actionsCreators>) {
    return { actions : bindActionCreators(actionsCreators, dispatch) };
}

const MySmarthComponent = connect(mapStateToProps, mapDispatchToProps)(MyComponent);

Answer 3

Answer №2

In order to properly define the state type and return type, you can utilize the following code snippet:

function mapStateToProps (state: any): any {
  return {
    deals: state.deals
  };
}

If you have specific type definitions or classes, feel free to replace the any with them.

Here are some default types that you may find useful:

any
string
number

Answer 4

In order to properly define the state type and return type, you can utilize the following code snippet:

function mapStateToProps (state: any): any {
  return {
    deals: state.deals
  };
}

If you have specific type definitions or classes, feel free to replace the any with them.

Here are some default types that you may find useful:

any
string
number

Definition of Redux store state object

Answer №1

Answer №2

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