React Native Redux createStore错误：未定义不是对象（正在评估“ action.type”）

Question

我将Redux与ReactNative一起使用，我想用reducer创建一个商店

而且，我在下面遇到错误，在reducer.js中的功能switchToTab（）中指向行“ switch（action.type）”

undefined is not an object(evaluating 'action.type')

这是我的actions.js

export const SWITCH_TAB = 'switchTab'

export function switchTab(index) {

return {
    type: SWITCH_TAB,
    index: index
}

}

这是我的reducer.js

import { SWITCH_TAB } from './actions.js'

export function switchToTab(state = {}, action) {

switch (action.type) {//error point to this line

    case SWITCH_TAB:
        return Object.assign({}, ...state, {
            index: action.index
        });
    break;

    default:
        return state;
}

}

这是createStore：

import { createStore } from 'redux';
import { switchToTab } from './reducer.js'

export default class MainPage extends Component {
    constructor(props) {
    super(props);
    this.state = {
        index:0
    };

    let store = createStore(switchToTab());
}

Answer 1

创建商店时，您无需致电reducer。 createStore接受一个reducer函数作为其第一个参数。

import { createStore } from 'redux';
import { switchToTab } from './reducer.js'

export default class MainPage extends Component {
    constructor(props) {
    super(props);
    this.state = {
        index:0
    };

    let store = createStore(switchToTab); // dont call this here, just pass it
}