I'm trying to pass an array of data as props (using context) to another component Carousello.js
But I’m unable to retrieve data on my Home.js component.
This is My HomeContext.js Component:
I use context to calling the API and then passing data to Home.js
import React, { useState, createContext } from 'react';
import axios from 'axios'
export const HomeContext = createContext();
export const HomeProvider = (props) => {
let array = []
axios.get(`/wordpress/wp-json/wp/v2/pages/15`)
.then(function (res) {
let slider = res.data.acf.slider
array.push(slider)
})
console.log(typeof (array))
let ar = array.flat()
console.log(ar)
return (
<HomeContext.Provider value={[array]}>
{props.children}
</HomeContext.Provider>
)
}
This is my Carosello.js component where i try to retrive data and render it with jsx:
import React, { Component, useContext } from 'react'
import sfondo from './sfondo-gray.jpg'
import { HomeProvider, HomeContext } from './HomeContext';
const Carosello = () => {
const [acf] = useContext(HomeContext)
console.log(acf)
return (
<div id="myCarousel" className="carousel slide" data-ride="carousel" >
<h1> {acf.title} </h1>
</div >
)
}
export default Carosello
You probably also need to wrap your axios call in a function to use inside useEffect. For more detailed info on that, check these: A complete guide to useEffect and fetchind data with useEffect. Basically, using the [] (empty list of dependencies) to trigger one-time action doesn't always work as you would expect from class components' componentDidMount.
export const HomeProvider = (props) => {
const [array, setArray] = useState([]);
useEffect(()=> {
function fetchData() {
axios.get(`/wordpress/wp-json/wp/v2/pages/15`)
.then(function (res) {
let slider = res.data.acf.slider
setArray([...slider.flat()])
})
}
fetchData();
}, [])
return (
<HomeContext.Provider value={[array]}>
<>{props.children}</>
</HomeContext.Provider>
)
}
import React, { useState, createContext } from 'react';
import axios from 'axios'
export const HomeContext = createContext();
export const HomeProvider = ({children}) => {
// array type
const [items, setItems] = useState([])
axios.get(`/wordpress/wp-json/wp/v2/pages/15`)
.then(function (res) {
let slider = res.data.acf.slider
setItems([...slider.flat()])
})
return (
<HomeContext.Provider value={{
array:items
}}>
{children}
</HomeContext.Provider>
)
}
const Carosello = () => {
// object destructuring
const {array} = useContext(HomeContext)
return (
<div id="myCarousel" className="carousel slide" data-ride="carousel" >
{/* if is array, try to map or [key] */}
<h1> {array[0].title} </h1>
</div >
)
}
export default Carosello
`
function HomeProvider(){
const [array, setArray] = React.useState([]);
React.useEffect(()=> {
axios.get(`/wordpress/wp-json/wp/v2/pages/15`)
.then(function (res) {
let slider = res.data.acf.slider
setArray((arr)=> [...arr, slider])
})
}, [])
return (
<HomeContext.Provider value={[array]}>
{props.children}
</HomeContext.Provider>
)
}
Related
I want to display a list of products in one of my components. I need to use UseEffect to get the results of a function that returns a promise. I then am setting state in UseEffect but am having trouble displaying the products. The state is getting updated but I am not able to render the results on the dom.
Here's the component:
import React, { useEffect, useState } from "react"
import styled from "styled-components"
import pullShopifyData from "../../functions/shopify"
export default function DataPreview(props)
const { apiKey } = props
const [data, setData] = useState([])
useEffect(() => {
pullShopifyData(apiKey).then(response => {
console.log(response.data.shop.products)
setData(response.data.shop.products)
})
}, [])
return (
<Wrapper>
{data.length > 0 ? data.map(product => (
<ProductWrapper>{product}</ProductWrapper>
)): <NoProductsWrapper>No Products Found</NoProductsWrapper>}
</Wrapper>
)
}
const Wrapper = styled.div``
const ProductWrapper = styled.div``
const NoProductsWrapper = styled.div``
Here's the output on the dom:
Move your data fetch function in to async wrapper function. Then just call it in useEffect.
useEffect(() => {
fetchSomething();
}, [])
const fetchSomething = async () => {
const response = await pullShopifyData(apiKey);
console.log(response.data.shop.products)
setData(response.data.shop.products)
}
I'm learning React and am having trouble with a value defined in a custom context provider. I access the value in a component under the provider with a custom hook but it's reported as being undefined. I've gone through the questions on SO and have verified my syntax with the lesson in my book but can't find the problem.
This is my custom provider and custom hook:
import React, { createContext, useState, useEffect, useContext } from 'react';
const ApiContext = createContext();
export const useApi = () => useContext(ApiContext);
export const ApiProvider = ({ children }) => {
const [loading, setLoading] = useState(false);
const [error, setError] = useState();
const [baseImageUrl, setBaseImageUrl] = useState();
const apiKey = 'api_key=SECRET';
const baseUrl = 'https://api.themoviedb.org/3';
const objToParams = (obj) => {
let params = '';
if(obj) {
const keys = Object.keys(obj);
for(let key of keys) {
params += `&${key}=${encodeURIComponent(obj[key])}`;
}
}
return params;
}
const api = {
get: async (path, params) => {
const resp = await fetch(baseUrl + path + '?' + apiKey + objToParams(params));
return await resp.json();
}
}
useEffect( () => {
try {
setLoading(true);
const config = api.get('/configuration');
console.log(config);
config.images && setBaseImageUrl(config.images.secure_base_url);
}
catch (error) {
console.error(error);
setError(error);
}
finally {
setLoading(false);
}
}, []);
if( loading ) {
return <p>Loading...</p>;
}
if( error ) {
return <pre>{JSON.stringify(error, null, 2)}</pre>;
}
return (
<ApiContext.Provider value={{ api, baseImageUrl }}>
{ children }
</ApiContext.Provider>
);
}
and this is the component where I access the value through the custom hook:
import React, { useState } from 'react';
import { ApiProvider, useApi } from './components/context/ApiProvider';
import Header from './components/Header';
import Main from './components/Main';
import Footer from './components/Footer';
import './App.css';
const App = () => {
const [searching, setSearching] = useState(false);
const [searchResults, setSearchResults] = useState([])
const [searchError, setSearchError] = useState();
const {api} = useApi();
const onSearch = (query) => {
try {
setSearching(true);
setSearchResults(api.get('/search/multi', {query: encodeURIComponent(query)} ));
console.log(searchResults);
}
catch (error) {
console.error(error);
setSearchError(error);
}
finally {
setSearching(false);
}
}
return (
<ApiProvider>
<div className="main-layout">
<Header onSearch={ onSearch }/>
<Main
searching={ searching }
searchError={ searchError }
searchResults={ searchResults }
/>
<Footer />
</div>
</ApiProvider>
);
}
export default App;
You can't consume the context in the component where you apply it.
<ComponentA>
<Context.Provider value={"somethong"} >
<ComponentB/>
</Context.Provider>
</ComponentA>
In the above example, only ComponentB can consume the value. ComponentA can't.
If you wan't to consume the value in your App component, it has to be the child (or grandchild ...) of the ContextProvider.
<Context.Provider value={"somethong"} >
<App/>
</Context.Provider>
If I understand your code correctly than you are trying to consume the context in your App, while also returning the provider for the same context.
I'm creating React context but it returns a promise. In the file playlistcontext.js I've the following code:
import React, { useEffect } from 'react';
import YouTube from '../services/youtube';
const playlistsData = YouTube.getPlaylists();
// console.log(playlistsData);
const PlaylistsDataContext = React.createContext(playlistsData);
const PlaylistsDataProvider = (props) => {
const [playlists, setPlaylists] = React.useState(playlistsData);
useEffect(() =>{
const playlistsData = YouTube.getPlaylists();
console.log(playlistsData);
setPlaylists(playlistsData);
},[])
return <PlaylistsDataContext.Provider value={[playlists, setPlaylists]}>{props.children}</PlaylistsDataContext.Provider>;
}
export {PlaylistsDataContext, PlaylistsDataProvider};
In the file youtube.js, that I use it like a service, I'have the code below. In this function a console.log(result.data) return me the correct data.
import axios from 'axios';
import { YOUTUBE_API } from '../config/config';
function Youtube() {
const handleError = (resp) => {
let message = '';
switch (+resp.status) {
case 401:
message = resp.data.error;
break;
default:
message = 'general error';
}
return message;
}
const getPlaylists = async () => {
try {
const result = await axios.get(YOUTUBE_API + '');
return result.data;
} catch(e) {
return Promise.reject(handleError(e.response));
}
}
return {
getPlaylists
}
}
const ytMethod = Youtube();
export default ytMethod;
then, I have a containers "tutorialcontainer.js" in which I've wrapped a component:
import React, {useState} from 'react';
import { PlaylistsDataProvider } from '../containers/playlistscontext';
import Tutorials from '../components/tutorials';
const TutorialsContainer = (props) => {
return (
<PlaylistsDataProvider>
<Tutorials />
</PlaylistsDataProvider>
);
}
export default TutorialsContainer;
In the last file tutorials.js I have the component. In this file the console.log(playlist) returns me a promise.
import React, {useState, useEffect} from 'react';
import SectionBoxPlaylist from '../components/html_elements/card_playlist';
import Header from '../components/header';
import { PlaylistsDataContext } from '../containers/playlistscontext';
const Tutorials = (props) => {
const [playlists, setPlaylists] = React.useContext(PlaylistsDataContext);
return (
<div className="app-container">
<Header />
<div className="section section-one text-center">
<div className="section-content">
<div className="section-box-items">
{
Object.keys(playlists).map((item) => {
return <SectionBoxPlaylist key={item} id={item} info={playlists[item]} />
})
}
</div>
</div>
</div>
</div>
);
}
export default Tutorials;
Can you help and explain me why?
Thank you!
setPlaylists is called immediately after YouTube.getPlaylists().
useEffect(() => {
const playlistsData = YouTube.getPlaylists();
console.log(playlistsData); // playlistsData is not fetched
setPlaylists(playlistsData);
},[])
You should be able to use .then():
YouTube.getPlaylists().then(response => {
console.log(response);
setPlaylists(response);
});
You can also create async function inside useEffect():
useEffect(() => {
const getYTPlaylist = async () => {
const playlistsData = await YouTube.getPlaylists();
console.log(playlistsData);
setPlaylists(playlistsData);
}
getYTPlaylist();
},[])
I'm quite new to React Hooks/Context so I'd appreciate some help. Please don' t jump on me with your sharp teeth. I Checked other solutions and some ways i've done this before but can't seem to get it here with the 'pick from the list' way.
SUMMARY
I need to get the municipios list of names inside of my const 'allMunicipios'(array of objects) inside of my Search.js and then display a card with some data from the chosen municipio.
TASK
Get the data from eltiempo-net REST API.
Use Combobox async element from Elastic UI to choose from list of municipios.
Display Card (from elastic UI too) with some info of chosen municipio.
It has to be done with function components / hooks. No classes.
I'd please appreciate any help.
WHAT I'VE DONE
I've created my reducer, context and types files in a context folder to fecth all data with those and then access data from the component.
I've created my Search.js file. Then imported Search.js in App.js.
I've accesed the REST API and now have it in my Search.js
PROBLEM
Somehow I'm not beeing able to iterate through the data i got.
Basically i need to push the municipios.NOMBRE from api to the array const allMunicipios in my search.js component. But when i console log it it gives me undefined. Can;t figure out why.
I'll share down here the relevant code/components. Thanks a lot for whoever takes the time.
municipiosReducer.js
import {
SEARCH_MUNICIPIOS,
CLEAR_MUNICIPIOS,
GET_MUNICIPIO,
GET_WEATHER,
} from "./types";
export default (state, action) => {
switch (action.type) {
case SEARCH_MUNICIPIOS:
return {
...state,
municipios: action.payload,
};
case GET_MUNICIPIO:
return {
...state,
municipio: action.payload,
};
case CLEAR_MUNICIPIOS:
return {
...state,
municipios: [],
};
case GET_WEATHER: {
return {
...state,
weather: action.payload,
};
}
default:
return state;
}
};
municipiosContext.js
import { createContext } from "react";
const municipiosContext = createContext();
export default municipiosContext;
MunicipiosState.js
import React, { createContext, useReducer, Component } from "react";
import axios from "axios";
import MunicipiosContext from "./municipiosContext";
import MunicipiosReducer from "./municipiosReducer";
import {
SEARCH_MUNICIPIOS,
CLEAR_MUNICIPIOS,
GET_MUNICIPIO,
GET_WEATHER,
} from "./types";
const MunicipiosState = (props) => {
const initialState = {
municipios: [],
municipio: {},
};
const [state, dispatch] = useReducer(MunicipiosReducer, initialState);
//Search municipios
//In arrow functions 'async' goes before the parameter.
const searchMunicipios = async () => {
const res = await axios.get(
`https://www.el-tiempo.net/api/json/v2/provincias/08/municipios`
// 08 means barcelona province. This should give me the list of all its municipios
);
dispatch({
type: SEARCH_MUNICIPIOS,
payload: res.data.municipios,
});
};
//Get Municipio
const getMunicipio = async (municipio) => {
const res = await axios.get(
`https://www.el-tiempo.net/api/json/v2/provincias/08/municipios/${municipio.CODIGOINE}`
//CODIGOINE is in this REST API kind of the ID for each municipio.
//I intent to use this later to get the weather conditions from each municipio.
);
dispatch({ type: GET_MUNICIPIO, payload: res.municipio });
};
const dataMunicipiosArray = [searchMunicipios];
//Clear Municipios
const clearMunicipios = () => {
dispatch({ type: CLEAR_MUNICIPIOS });
};
return (
<MunicipiosContext.Provider
value={{
municipios: state.municipios,
municipio: state.municipio,
searchMunicipios,
getMunicipio,
clearMunicipios,
dataMunicipiosArray,
}}
>
{props.children}
</MunicipiosContext.Provider>
);
};
export default MunicipiosState;
Search.js
import "#elastic/eui/dist/eui_theme_light.css";
import "#babel/polyfill";
import MunicipiosContext from "../contexts/municipiosContext";
import MunicipiosState from "../contexts/MunicipiosState";
import { EuiComboBox, EuiText } from "#elastic/eui";
import React, { useState, useEffect, useCallback, useContext } from "react";
const Search = () => {
const municipiosContext = useContext(MunicipiosContext);
const { searchMunicipios, municipios } = MunicipiosState;
useEffect(() => {
return municipiosContext.searchMunicipios();
}, []);
const municipiosFromContext = municipiosContext.municipios;
const bringOneMunicipio = municipiosContext.municipios[0];
let municipiosNames = municipiosFromContext.map((municipio) => {
return { label: `${municipio.NOMBRE}` };
});
console.log(`municipiosFromContext`, municipiosFromContext);
console.log(`const bringOneMunicipio:`, bringOneMunicipio);
console.log(`municipiosNames:`, municipiosNames);
const allMunicipios = [
{ label: "santcugat" },
{ label: "BARCELONETA" },
{ label: "BARCE" },
];
const [selectedOptions, setSelected] = useState([]);
const [isLoading, setLoading] = useState(false);
const [options, setOptions] = useState([]);
let searchTimeout;
const onChange = (selectedOptions) => {
setSelected(selectedOptions);
};
// combo-box
const onSearchChange = useCallback((searchValue) => {
setLoading(true);
setOptions([]);
clearTimeout(searchTimeout);
// eslint-disable-next-line react-hooks/exhaustive-deps
searchTimeout = setTimeout(() => {
// Simulate a remotely-executed search.
setLoading(false);
setOptions(
municipiosNames.filter((option) =>
option.label.toLowerCase().includes(searchValue.toLowerCase())
)
);
}, 1200);
}, []);
useEffect(() => {
// Simulate initial load.
onSearchChange("");
}, [onSearchChange]);
return (
<div>
<EuiComboBox
placeholder="Search asynchronously"
async
options={options}
selectedOptions={selectedOptions}
isLoading={isLoading}
onChange={onChange}
onSearchChange={onSearchChange}
/>
<button>Lista de municipios</button>
</div>
);
};
export default Search;
also the
Home.js
import React, { useState } from "react";
import { EuiComboBox, EuiText } from "#elastic/eui";
// import { DisplayToggles } from "../form_controls/display_toggles";
import "#babel/polyfill";
import "#elastic/eui/dist/eui_theme_light.css";
import Search from "./Search";
import MunicipioCard from "./MunicipioCard";
const Home = () => {
return (
<div>
<EuiText grow={false}>
<h1>Clima en la provincia de Barcelona</h1>
<h2>Por favor seleccione un municipio</h2>
</EuiText>
<Search />
<MunicipioCard />
</div>
);
};
export default Home;
App.js
import "#babel/polyfill";
import "#elastic/eui/dist/eui_theme_light.css";
import { EuiText } from "#elastic/eui";
import React from "react";
import Home from "./components/Home";
import MunicipiosState from "./contexts/MunicipiosState";
import "./App.css";
function App() {
return (
<MunicipiosState>
<div className="App">
<EuiText>
<h1>App Component h1</h1>
</EuiText>
<Home />
</div>
</MunicipiosState>
);
}
export default App;
You are using forEach and assigning the returned value to a variable, however forEach doesn't return anything. You should instead use map
let municipiosNames = municipiosFromContext.map((municipio) => {
return `label: ${municipio.NOMBRE}`;
});
As per your comment:
you data is loaded asynchronously, so it won't be available on first render and since functional components depend on closures, you onSearchChange function takes the value from the closure at the time of creation and even if you have a setTimeout within it the updated value won't reflect
The solution here is to add municipiosFromContext as a dependency to useEffect
const onSearchChange = useCallback((searchValue) => {
setLoading(true);
setOptions([]);
clearTimeout(searchTimeout);
// eslint-disable-next-line react-hooks/exhaustive-deps
searchTimeout = setTimeout(() => {
// Simulate a remotely-executed search.
setLoading(false);
setOptions(
municipiosNames.filter((option) =>
option.label.toLowerCase().includes(searchValue.toLowerCase())
)
);
}, 1200);
}, [municipiosFromContext]);
useEffect(() => {
// Simulate initial load.
onSearchChange("");
}, [onSearchChange]);
I am using Easy Peasy State management for React. I would like to create multiple Axios call from one store location and import it in each page there where I need to show the correct data. I am trying to fetch a JSON placeholder data for example and use that inside a component to push it to the state using Hooks.
But I get the following error:
model.js:14 Uncaught (in promise) TypeError: actions.setTodos is not a function
at model.js:14
Can someone help me out? What am I doing wrong?
My code for the store (model.js):
import { thunk } from 'easy-peasy';
export default {
todos: [],
fetchTodos: thunk(async actions => {
const res = await fetch(
'https://jsonplaceholder.typicode.com/todos?_limit=10'
);
const todos = res.json();
actions.setTodos(todos);
}),
};
My Page component Contact:
import React, { useState, useEffect } from 'react';
import { useStoreActions } from 'easy-peasy';
import ReactHtmlParser from 'react-html-parser';
import { API_URL } from 'constants/import';
// import axios from 'axios';
const Contact = () => {
const [contactPage, setContactPage] = useState([]);
const { page_title, page_content, page_featured_image } = contactPage;
const fetchTodos = useStoreActions(actions => actions.fetchTodos);
useEffect(() => {
fetchTodos();
}, []);
return (
<section className="contact">
<div className="page">
<div className="row">
<div className="col-xs-12">
<h3 className="section__title">{page_title}</h3>
{ReactHtmlParser(page_content)}
{page_featured_image && (
<img src={API_URL + page_featured_image.path} />
)}
</div>
</div>
</div>
</section>
);
};
export default Contact;
You need to use action.
import { action, thunk } from "easy-peasy";
export default {
fetchTodos: thunk(async (actions, payload) => {
const res = await fetch(
"https://jsonplaceholder.typicode.com/todos?_limit=10"
);
const todos = res.json();
actions.setTodos(todos);
}),
todos: [],
setTodos: action((state, payload) => {
console.log("---->>> payload!")
state.todos = payload
}),
};
I usually use it like this, it works perfectly for me.