如何在 redux 中使用 API 调用操作? [英] How to work with API call action in redux?

问题描述

我是 redux 的新手，我正在尝试让它与我的应用程序一起使用，但是我在理解如何使用其中的异步操作时遇到了问题.我有 api 调用的操作.一旦我的其他状态不为空，就应该调用此操作.我没有犯任何错误，但我认为我的操作没有被调用，因为数据是空的.任何人都可以帮助理解我做错了什么吗?

I am new to redux and I am trying to make it work with my application, but I have problems with understanding how to work with async actions in it. I have action that is api call. This action should be called as soon as my other state is not empty. I do not get any mistakes but do not think that my action is called since the data is empty. Can anybody help to understand what I am doing wrong?

这是我的 actions.js.wordsFetchData 是我需要调用的操作:

Here is my actions.js. The wordsFetchData is the action I need to call:

 export function wordsFetchDataSuccess(items){
    return{
        type: 'WORDS_FETCH_DATA_SUCCESS',
        items
    };
 }

 export function wordsAreFetching(bool){
     return{
        type: 'WORDS_ARE_FETCHING',
        areFetching: bool
     }
 }

 export function wordsHasErrored(bool) {
     return {
        type: 'WORDS_HAS_ERRORED',
        hasErrored: bool
     };
 }

 export function wordsFetchData(parsed) {
    return (dispatch) => {
        dispatch(wordsAreFetching(true));

        fetch('URL', {
            method: "POST",
            headers: {
                "Content-type": "application/json"
            },body: JSON.stringify({
                 words: parsed
        })
    })
        .then((response) => {
            if (!response.ok) {
                throw Error(response.statusText);
            }

            dispatch(wordsAreFetching(false));

            return response;
        })
        .then((response) => response.json())
        .then((items) => dispatch(wordsFetchDataSuccess(items)))
        .catch(() => dispatch(wordsHasErrored(true)));
    };
 }

这是我的减速器:

export function word(state = [], action) {
switch (action.type) {
    case 'WORDS_FETCH_DATA_SUCCESS':
        return action.items;

    default:
        return state;
    }
}

export function wordsAreFetching(state = false, action) {
    switch (action.type) {
        case 'WORDS_ARE_FETCHING':
            return action.areFetching;

        default:
            return state;
    }
}

export function wordsFetchHasErrored(state = false, action) {
    switch (action.type) {
        case 'WORDS_HAS_ERRORED':
           return action.hasErrored;

    default:
        return state;

    }

 }

这是我的 componentDidMount 函数:

This is my componentDidMount function:

componentDidMount = (state) => {
    this.props.fetchData(state);
};

这是终止后应该调用哪个动作的函数:

This is the function after terminating which the action should be called:

 parseInput = async () => {
    console.log(this.state.textInput);
    let tempArray = this.state.textInput.split(" "); // `convert 
    string into array`
    let newArray = tempArray.filter(word => word.endsWith("*"));
    let filterArray  = newArray.map(word => word.replace('*', ''));
    await this.setState({filterArray: filterArray});
    await this.props.updateData(this.state.filterArray);
    if (this.state.projectID === "" && this.state.entity === "")
        this.dialog.current.handleClickOpen();
    else
        if (this.state.filterArray.length !== 0)
            this.componentDidMount(this.state.filterArray);
    };

这些是 mapStateToProps 和 mapDispatchToProps 函数.

These are the mapStateToProps and mapDispatchToProps functions.

const mapStateToProps = (state) => {
    return {
        items: state.items,
        hasErrored: state.wordsFetchHasErrored,
        areFetching: state.wordsAreFetching
    };
};

const mapDispatchToProps = (dispatch) => {
    return {
        fetchData: wordsFetchData
    };
};

推荐答案

执行抓取只需要一个动作(即WORDS_ARE_FETCHING)，其他情况(即WORDS_HAS_ERRORED)code> & WORDS_FETCH_DATA_SUCCESS) 可以在你的 reducer 中处理.

You only need one action for executing fetching (i.e WORDS_ARE_FETCHING), the rest of the cases (i.e WORDS_HAS_ERRORED & WORDS_FETCH_DATA_SUCCESS) can be handled inside your reducer.

您的操作:

 export function wordsAreFetching(){
     return{
        type: 'WORDS_ARE_FETCHING',
     }
 }

你的新减速器:

export function word(state = [], action) {
switch (action.type) {
    case 'WORDS_ARE_FETCHING':
        return {...state, error: false, areFetching: true};
    case 'WORDS_FETCH_DATA_SUCCESS':
        return {...state, items: action.payload , areFetching: false};
    case 'WORDS_HAS_ERRORED':
        return {...state, error: true, areFetching: false};
    default:
        return state;
}

然后你可以在你从这里获取数据后触发WORDS_FETCH_DATA_SUCCESS:

Then you can trigger WORDS_FETCH_DATA_SUCCESS after you get the data from here:

export function wordsFetchData() {
    try {
        const response = await axios.get(YOUR_URL);
        return dispatch({ type: WORDS_FETCH_DATA_SUCCESS, payload: response.data });
    } catch (err) {
        return dispatch({ type: WORDS_HAS_ERRORED });
    }
 }

看看这个示例，它使用了可以帮助您进行异步调用的 axios.

Take a look at this example, it uses axios that can help you with async calls.

这篇关于如何在 redux 中使用 API 调用操作?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！