mapStateToProps 必须 return 一个对象。而是收到 Map{}？

Question

你好，我对状态使用不可变映射，当我尝试使用 mapStateToProps 时出现此错误。

Uncaught Invariant Violation: mapStateToProps must return an object. Instead received Map {}.

这是我的代码：

组件：

    const mapStateToProps = (state) => {
      return state
    }

     class LoanCalculator extends React.Component{

      componentWillMount(){
       this.dispatch(loadConstraints());
     }

      render(){
        return (
          <div>
            <h1> Loan Calculator </h1>
            <SlidersBox {...this.props}/>
         </div>
       )
     }
   }

    LoanCalculator = connect(
      mapStateToProps
    )(LoanCalculator)

   export default LoanCalculator

减速机

    import { Map } from 'immutable'
    import {LOAD_CONSTRAINTS, SET_AMOUNT_VALUE, SET_TERM_VALUE} from "../actions/actions";

    const initialState = new Map();

    export default function calculator(state = initialState, action){
      switch (action.type){
        case LOAD_CONSTRAINTS:
          return  state.set("constraints", action.constraints)
         case SET_AMOUNT_VALUE:
           return state.set("selectedAmount", action.amount)
        case SET_TERM_VALUE:
         return state.set("selectedTerm", action.term)
        default:
          return state
      }
    }

Answer 1

这个 github 问题涵盖了这个确切的问题：https://github.com/reactjs/react-redux/issues/60。

您可以在 mapStateToProps 函数中手动从地图中提取所需的值：

const mapStateToProps = (state) => {
  return {
       constraints: state.get('constraints'),
       selectedAmount: state.get('selectedAmount'),
       selectedTerm: state.get('selectedTerm'),
  };
}

mapStateToProps 必须 return 一个对象。而是收到 Map{}？

mapStateToProps must return an object. Instead received Map {}?

reactjs

immutable.js

redux

react-redux