CODEWITHSUNDEEP
javascriptreactjsfetchgiphygiphy-api
Tomas Engquist
Tomas Engquist

Reputation: 23

How to wait for fetch to complete before rendering page in React.js

In this React component, I'm trying to fetch data from the GIPHY API and render it in another component. The fetch is working correctly, but this.state.gifs.map returns an error because it runs before the fetch is complete and the state is set. I have tried using Hooks with async/await but that did not seem to work either. How can I create my gifArray after the state is set so I'm not trying to run .map on an empty array.

import React, {Component} from 'react'
import GifCard from './gifCard.js'
import './App.css'

export default class GifContainer extends Component{

  state = {
    gifs: []
  }

  componentDidMount(){
    fetch('http://api.giphy.com/v1/gifs/search?q=ryan+gosling&api_key=KnzVMdxReB873Hngy23QGKAJh6WtUnmz&limit=5')
    .then(res => res.json())
    .then(gifs => {
      this.setState({gifs})
    })
  }


  render(){
    const gifArray = this.state.gifs.map((gif) => {
      return <GifCard key={gif.name} gif={gif}/>
    })
    return(
      <div>
        <h1 id="heading">Gif Search</h1>
        <div id='gifContainer'>
          {gifArray}
        </div>
      </div>

    )}

}

Upvotes: 2

Views: 14130

Answers (2)

smashed-potatoes
smashed-potatoes

Reputation: 2222

Your loading and state management is actually fine - running map on an empty array will not result in an error.

Your issue is actually with the data you are getting back. I checked the response of the URL you are using and it returns an object with the data and paging details like this:

{
  data: [
    // The gif array
  ],
  pagination: {...},
  meta: {...}
}

Using map on this object will give you an error. The gif array is in the data property which you should use - e.g. instead of:

this.setState({gifs})

You can use:

this.setState({gifs: gifs.data})

Upvotes: 3

boosted_duck
boosted_duck

Reputation: 508

You have to check first if gifs array is not empty. When the setState is done, render will trigger again, and this time there will be gifs to map.

    let gifArray = '';

    if (this.state.gifs.length > 0) {
        gifArray = this.state.gifs.map((gif) => {
          return <GifCard key={gif.name} gif={gif}/>
        })
    }

Upvotes: 4

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