Use async react-select with redux-saga

问题

I try to implement a async react-select (Select.Async). The problem is, we want to do the fetch in redux-saga. So if a user types something, the fetch-action should be triggered. Saga then fetches the record and saved them to the store. This works so far. Unfortunately loadOptions has to return a promise or the callback should be called. Since the newly retrieved options get propagated with a changing property, I see no way to use Select.Async together with saga to do the async fetch call. Any suggestions?

 <Select.Async
   multi={false}
   value={this.props.value}
   onChange={this.onChange}
   loadOptions={(searchTerm) =>  this.props.options.load(searchTerm)}
  />

I had a hack where i assigned the callback to a class variable and resolve it on componentWillReceiveProps. That way ugly and did not work properly so i look for a better solution.

Thanks

回答1:

redux-saga is for handling side effects like asynchronously receiving options for react-select. That's why you should leave the async stuff to redux-saga. I have never used react-select but by just looking at the documentation I would solve it this way:

Your component gets very simple. Just get value and options from your redux store. optionsRequested is an action creator for the OPTIONS_REQUESTED action:

const ConnectedSelect = ({ value, options, optionsRequested }) => (
  <Select
    value={value}
    options={options}
    onInputChange={optionsRequested}
  />
)

export default connect(store => ({
  value: selectors.getValue(store),
  options: selectors.getOptions(store),
}), {
  optionsRequested: actions.optionsRequested,
})(ConnectedSelect)

A saga definition watches for OPTIONS_REQUESTED action that is trigged by onInputChange, loads the data with given searchTerm from server and dispatches OPTIONS_RECEIVED action to update redux store.

function* watchLoadOptions(searchTerm) {
  const options = yield call(api.getOptions, searchTerm)
  yield put(optionsReceived(options))
}

In other words: Make your Component as pure as possible and handle all side-effect/async calls in redux-saga

I hope this answer was useful for you.

回答2:

The main idea is that you are capable to dispatch redux actions using application context from

import React from 'react';
import { connect } from 'react-redux';

import Select from '@components/Control/Form/Skin/Default/Select';
import { reduxGetter, reduxSetter, required as req } from '@helpers/form';
import { companyGetTrucksInit } from "@reduxActions/company";

import AppContext from '@app/AppContext';

const FIELD_NAME = 'truck';

export const getReduxValue = reduxGetter(FIELD_NAME);
export const setReduxValue = reduxSetter(FIELD_NAME);

const SelectCompanyTruck = (props) => {
    const {
        required,
        validate=[]
    } = props;

    const vRules = [...validate];

    if (required)
        vRules.push(req);


    return (
        <AppContext.Consumer>
            {({ dispatchAction }) => (
                <Select
                    loadOptions={(inputValue, callback) => {
                        function handleResponse(response) {
                            const { data: { items } } = response;
                            const options = items.map(i => ({ label: i.name, value: i.id }));

                            callback(options);
                        }

                        dispatchAction(companyGetTrucksInit, { resolve: handleResponse, inputValue });
                    }}
                    name={FIELD_NAME}
                    {...props}
                />
            )}
        </AppContext.Consumer>
    );
}

export default SelectCompanyTruck;

来源：https://stackoverflow.com/questions/43072867/use-async-react-select-with-redux-saga