NextJS: How to add screen loading for production build? - reactjs

Question

I want add screen loading in next js project. And I tried to do that with the Router component in next/router.
This is my _app.js in next.js project:
import {CookiesProvider} from 'react-cookie';
import App from 'next/app'
import React from 'react'
import {Provider} from 'react-redux'
import withRedux from 'next-redux-wrapper'
import withReduxSaga from 'next-redux-saga'
import createStore from '../src/redux/store'
import Router from "next/router";
import {Loaded, Loading} from "../src/util/Utils";
class MyApp extends App {
static async getInitialProps({Component, ctx}) {
let pageProps = {};
if (Component.getInitialProps) {
pageProps = await Component.getInitialProps({ctx})
}
return {pageProps}
}
render() {
Router.onRouteChangeStart = () => {
Loading()
};
Router.onRouteChangeComplete = () => {
Loaded()
};
Router.onRouteChangeError = () => {
Loaded()
};
const {Component, pageProps, store} = this.props;
return (
<CookiesProvider>
<Provider store={store}>
<Component {...pageProps} />
</Provider>
</CookiesProvider>
)
}
}
export default withRedux(createStore)(withReduxSaga(MyApp))
This is Loaded() and Loading() functions:
export const Loaded = () => {
setTimeout(() => {
let loading = 'has-loading';
document.body.classList.remove(loading);
}, 100);
};
export const Loading = () => {
let loading = 'has-loading';
document.body.classList.add(loading);
};
The code works well when the project is under development mode. But when the project is built, the loading won't disappear.
Do you know solution of this issue or are you suggesting another solution?

Answer 1

Using apollo client and react hooks you could do as follow.
Example:
import { useQuery } from '#apollo/react-hooks';
import gql from 'graphql-tag';
import { withApollo } from '../lib/apollo';
import UserCard from '../components/UserCard';
export const USER_INFO_QUERY = gql`
query getUser ($login: String!) {
user(login: $login) {
name
bio
avatarUrl
url
}
}
`;
const Index = () => {
const { query } = useRouter();
const { login = 'default' } = query;
const { loading, error, data } = useQuery(USER_INFO_QUERY, {
variables: { login },
});
if (loading) return 'Loading...'; // Loading component
if (error) return `Error! ${error.message}`; // Error component
const { user } = data;
return (
<UserCard
float
href={user.url}
headerImg="example.jpg"
avatarImg={user.avatarUrl}
name={user.name}
bio={user.bio}
/>
);
};
export default withApollo({ ssr: true })(Index);
More info here: https://github.com/zeit/next.js/tree/canary/examples/with-apollo

Answer 2

I added the following codes to a wrapper component and the problem was resolved.
componentDidMount() {
Loaded();
}
componentWillUnmount() {
Loading();
}