React，Array obj上的TypeError（this.props.data.map不是函数）

Question

Thank you for stopping by to help. I am working with a react/redux app. One of the component is using a lifecyle method to retrieve data from an API. Once recieved, the data JSON data is held within an array. My initialState for the data coming back is an empty array.

When the component listening to the state change is mounted, the data is rendered on to the page, but then 2 seconds later I am getting a

Uncaught TypeError: jobs.map is not a function

Component making the API call using lifecyle method and listening for state change

import React, { Component } from 'react';
import { connect } from 'react-redux';
import { getJobs } from '../../actions';
import { Card, Grid, Image, Feed } from 'semantic-ui-react';
// import './home.css';

const renderJobs = jobs => jobs.map((job, i) => (
    <Card.Group stackable key={i}>
      <Card className="jobscard">
        <Card.Content>
          <Card.Header href={job.detailUrl} target="_blank">{job.jobTitle}</Card.Header>
          <Card.Meta>{job.location}</Card.Meta>
          <Card.Description>{job.company}</Card.Description>
        </Card.Content>
      </Card>
    </Card.Group>
    ));

class GetJobs extends Component {

  componentDidMount() {
    this.props.getJobs();
  }

  render() {
    const { jobs } = this.props;
    return (
      <div className="getjobs">
        {renderJobs(jobs)}
      </div>
    );
  }
}

export default connect(({ jobs }) => ({ jobs }), { getJobs })(GetJobs);

Action creator/action

export const getJobsRequest = () => fetch('https://shielded-brushlands-43810.herokuapp.com/jobs',
)
 .then(res => res.json());

// action creator
export const getJobs = () => ({
  type: 'GET_JOBS',
  payload: getJobsRequest(),
});

Reducer

import initialState from './initialState';

export default function (jobs = initialState.jobs, action) {
  switch (action.type) {
    case 'GET_JOBS_PENDING':
      return { ...jobs, isFetching: true };
    case 'GET_JOBS_FULFILLED':
      return action.payload;
    case 'GET_JOBS_REJECTED':
      return jobs;
    default:
      return jobs;
  }
}

And intial state

export default {
  userData: {},
  jobs: [],
}

enter image description here

any thoughts on why this is happening?

Answer 1

您可以进行简单的检查，以确保作业准备就绪，然后再尝试呈现它。

{jobs.length && renderJobs(jobs)}