Cannot read property `.then` of undefined with axios and react in actions

问题

I am using axios in an action and trying to call that action with a chaining action. I will show what I am trying to do here:

this.props.fetchOffers().then(() => {
        this.props.filter(this.props.filterOption);
      });

But I get an error: Cannot read property 'then' of undefined.

What I do not get is that right below this function I have another action that is doing this exact same thing and working just fine.

  this.props.sortOffers(value).then(() => {
      this.props.filter(this.props.filterOption);
    });

Here is a working version of this.

Here is the actions file:

import axios from 'axios';
import { reset } from 'redux-form';

import { FETCH_OFFERS, SORT_OFFERS, FETCH_OFFER, GET_FILTER, PAYMENT_TYPE } from './types';

export function paginateOffers(indexPosition, numberOfItems) {
  return (dispatch) => {
    axios
      .get('/API/offers/pagination', {
        params: {
          position: indexPosition,
          number: numberOfItems,
        },
      })
      .then((response) => {
        dispatch({ type: FETCH_OFFERS, payload: response.data });
      })
      .catch((error) => {
        console.error(error);
      });
  };
}

export function fetchOffers() {
  return dispatch => {
    axios
      .get('/API/offers')
      .then((response) => {
        dispatch({ type: FETCH_OFFERS, payload: response.data });
      })
      .catch((err) => {
        console.error(err);
      });
  };
}

export function fetchOffer(id) {
  return (dispatch) => {
    axios
      .get(`/API/offers/${id}`)
      .then((response) => {
        dispatch({ type: FETCH_OFFER, payload: response.data.result });
      })
      .catch((err) => {
        console.error(`ERROR: ${err}`);
      });
  };
}

export function sortOffers(params) {
  const { price, title, category, type } = params;
  return dispatch =>
    axios
      .get('/API/offers/sort', {
        params: { price, title, category, type },
      })
      .then((response) => {
        dispatch({
          type: SORT_OFFERS,
          payload: response.data,
          sortOptions: params,
        });
        dispatch({
          type: PAYMENT_TYPE,
          payment: type,
        });
        dispatch(reset('sorter'));
      })
      .catch((err) => {
        console.error(err);
      });
}

export function getFilterOption(option) {
  return (dispatch) => {
    dispatch({
      type: GET_FILTER,
      option,
    });
  };
}

回答1:

You aren't returning a promise in your fetchOffers action creator. Notice the subtle difference in how you've declared your fat-arrow function.

Try this:

export function fetchOffers() {
  return dispatch => 
    axios
      .get('/API/offers')
      .then((response) => {
        dispatch({ type: FETCH_OFFERS, payload: response.data });
      })
      .catch((err) => {
        console.error(err);
      });
}

来源：https://stackoverflow.com/questions/46288816/cannot-read-property-then-of-undefined-with-axios-and-react-in-actions

标签

reactjs

promise

axios