image of the detail view with console to see the console.log()
I'm having troubles making the Tour Of Heroes Angular tutorial work, i'm in the 6 step of the tutorial, getting the data from a server but instead of getting the data from a simulated data server i have a api with nodejs express and mysql.
The problem cames when i try to show the detail of the hero (fetching one by id), all seems to work but the information don't show on the view.
template:
<div *ngIf="hero">
<h2>{{ hero.name }} Details</h2>
<div>id: {{hero.id}}</div>
<div>
<label for="name">Hero name: </label>
<input id="name" [(ngModel)]="hero.name" placeholder="name">
</div>
<button type="button" (click)="goBack()">go back</button>
</div>
component:
ngOnInit(): void {
this.getHero();
}
getHero(){
const id = Number(this.route.snapshot.paramMap.get("id"));
this.heroService.getHero(id).subscribe(hero => {
this.hero = hero;
console.log("hero", hero)
})
}
service:
private heroesUrl = 'http://localhost:3300/api/';
constructor(private MessageService: MessageService, private http: HttpClient) {
}
private log(message: string) {
this.MessageService.add(`HeroService: ${message}`);
}
getHeroes(): Observable<Hero[]>{
this.log('HeroService: fetched heroes');
return this.http.get<Hero[]>(this.heroesUrl);
}
getHero(id: number): Observable<Hero> {
const url = `${this.heroesUrl}${id}`;
return this.http.get<Hero>(url);
}
I don't know what's the problem, im learning angular but the observable is well suscribed, in the attached image you can see in the console that at least the api is working.
you received an array with an unique element, see the [``] in console. So
Or in subscribe your write hero[0]
this.heroService.getHero(id).subscribe(hero => {
this.hero = hero[0];
})
Or in your service return the first element of the array. For this use rxjs/operator map
getHero(id: number): Observable<Hero> {
const url = `${this.heroesUrl}${id}`;
return this.http.get<Hero[]>(url).pipe(
map((res:Hero[])=>res[0])
);
}
See that although you say to Angular that getHero return an Observable<Hero> really you got an Observable<Hero[]>. Yes, when we indicate the return of a function this not make "magically" we get the result, only help us to write the code and the editor advise us about it
Let's say I have a simple Angular Component:
#Component({
selector: 'app-email-content',
template: '<h1>Welcome {{username}}!</h1>'
})
export class WelcomeEmailComponent {
#Input() username: string
}
My goal is to take this Angular component and render it to plain HTML with Node.Js, to send customized EMails.
I know that Server-side rendering is definitely possible with Angular Universal. But I am not sure how to explicitly render one specific component.
The approach is to send an Angular component-based dynamically generated templates to users' email from the Angular SSR project.
Find the example repository at the bottom of this answer.
The steps you need to follow;
Design your templates in an individual routing path that is dedicated to showing only the email templates not your navigation bars, global CSS, etc.
Example:
welcome-email-component.component.ts
import { Component, OnInit } from '#angular/core';
import { ActivatedRoute } from '#angular/router';
#Component({
selector: 'app-welcome-email-component',
templateUrl: './welcome-email-component.component.html',
styleUrls: ['./welcome-email-component.component.css']
})
export class WelcomeEmailComponentComponent implements OnInit {
username: any;
constructor(private route: ActivatedRoute) { }
ngOnInit(): void {
this.route.params.subscribe(params => {
this.username = params.username;
});
}
}
welcome-email-component.component.html
<style>
.title-p {
color: #00025a;
font-size: 20px;
font-weight: bold;
}
</style>
<p class="title-p">Welcome {{username}}</p>
You need to specify a route for this component as below, so when the user navigates to the welcome-email/username route it should show only the email template generated component.
{ path: 'welcome-email/:username', component: WelcomeEmailComponentComponent }
Implement Angular SSR to your project from the great Angular SSR guidelines, Server-side rendering (SSR) with Angular Universal.
It's just two lines of code.
ng add #nguniversal/express-engine
npm run dev:ssr
Finally create a server-side API to generate the template from your Angular component and send emails or provide the HTML code of the single component, add the API function in your server.ts as below.
server.ts
server.get('/api/send-email/:username', (req, res) => {
// Below is the URL route for the Angular welcome mail component
request(`http://127.0.0.1:4200/welcome-email/${req.params.username}`, (error, response, body) => {
// TODO : Send email to the user from WelcomeEmailComponentComponent.ts component as `body`
// use the body to send email
res.send('Email sent');
});
});
Example code: https://github.com/aslamanver/angular-send-component-email
The demonstration of a dynamically generated component on this repository;
Finally when you access /api/send-email/:username, this will generate the welcome mail component and give the HTML body of that, thereafter you can proceed with your email sending function.
I clap #Googlian's answer. But, angular produces too much unfamiliar HTML5, CSS3 and angular specific bundled features, so after that you have to remove those one by one specifically if you want a real valid email content, otherwise your email most probably will be considered as spam bu mailclients.
I sugges that you mah have a component with xHTML standarts with no-CSS3, no-experimental HTML5 features, and build an email templete with this and ElementRef, then parse required fields manually.
Send the string to serverside, nodejs, then send it as email. You can use nodemailer
i am working in project where using model to show PDFTron webviewer. i am using model popup to load webviewer inside it when select pdf file from list.
first time it loads pdf document but when "clr-modal" open second time webviewer not load document.
//PdfviewerComponent html.
<div class="page">
<div #viewer class="viewer"></div>
</div>
export class PdfviewerComponent implements OnInit, AfterViewInit, OnChanges {
#ViewChild('viewer', { static: true }) viewer: ElementRef;
#Input() hash: string;
wvInstance: any;
constructor() { }
ngOnInit(): void { }
ngAfterViewInit(): void {
console.log('AfterViewInit called');
WebViewer({
path: '../assets/lib'
}, this.viewer.nativeElement).then(instance => {
this.wvInstance = instance;
const idtoken = localStorage.getItem('id_token');
const options = {
customHeaders: { Authorization: 'Bearer ' + idtoken }
};
const hash = this.hash.split(' ')[0];
const url = `/api/project/readfile/${hash}`;
this.wvInstance.loadDocument(url, options);
});
}
}
//popup in main component
<clr-modal [(clrModalOpen)]="openModel" >
<h3 class="modal-title">{{currentFileName}}</h3>
<div class="modal-body">
<app-pdfviewer [hash]="currentFileHash"></app-pdfviewer>
</div>
</clr-modal>
How does your popup modal work? Does it add "display:none" to hide the DOM element or does it remove the element from the DOM and add it back later?
If it removes the DOM element and add it back, there shouldn't be a problem (beside slower performance due to having to reload everything each time) as long as the WebViewer get re initialized.
If the popup is using "display:none", that is a problem. A lot of browsers have issues when using "display:none" with iframes (which WebViewer uses). If possible try using "visibility:hidde", "opacity:0", or "height: 0px" to hide the modal instead.
I have a component in React which displays (or doesn't at the moment) an image within an src tag.
The file path & file name of the image is passed via props after being selected by the user, so I can't do an import at the top of the file. Apparently, I should be able to do something like src={require(file)} but this causes webpack to throw a hissy fit and give the following error: Error: cannot find module "."
As an e.g., a typical filepath/filename I pass to the component is: '../../../images/black.jpg'
This is a stripped-down version of the code in question:
import React, { Component } from "react";
class DisplayMedia extends Component {
render() {
return (
<div className="imgPreview">
<img src={this.props.file} alt="piccy" />
</div>
);
}
}
export default DisplayMedia;
Depending on your set up...
If the images are dynamic (during production, images will be added, edited, or deleted):
I'd recommend a microservice that only handles images. I go in depth on how to approach such a service: Image returned from REST API always displays broken
If the images are static (during production, the images are bundled within the "bundle.js" file):
- I'd recommend importing all of the images within the component, creating an array of the imported images, and then utilizing the array index and React state to cycle through them. For example:
import React, { Component } from "react";
import Image1 from "../images/Image1.png";
import Image2 from "../images/Image2.png";
import Image3 from "../images/Image3.png";
const images = [Image1, Image2, Image3];
export default class ShowImage extends Component {
state = { index: 0 };
handleChange = ({ target: { value } }) => {
this.setState({ index: value });
};
render = () => (
<div className="container">
<h1>Utilizing Array Indexes</h1>
<select
style={{ marginBottom: 20 }}
value={this.state.index}
onChange={this.handleChange}
>
{images.map((val,idx) => (
<option key={idx} value={idx}>Image {idx + 1}</option>
))}
</select>
<img src={images[this.state.index]} />
</div>
);
}
While I can't create an exact codesandbox of the above, this working example should give you the basic idea: https://codesandbox.io/s/ovoo077685
You don't need to add require in src. When relative path is used it will go the images availale in your server but when url is given image will be loaded. You can find more info here
When using src as /images/black.jpg it will convert to localhost:3000/images/black.jpg
I'm having difficulty with differences between client-side and server-side rendering of styles in Material-UI components due to classNames being assigned differently.
The classNames are assigned correctly on first loading the page, but after refreshing the page, the classNames no longer match so the component loses its styling. This is the error message I am receiving on the Console:
Warning: Prop className did not match.
Server: "MuiFormControl-root-3 MuiFormControl-marginNormal-4
SearchBar-textField-31"
Client: "MuiFormControl-root-3 MuiFormControl-marginNormal-4
SearchBar-textField-2"
I've followed the Material-UI TextField example docs, and their accompanying Code Sandbox example, but I can't seem to figure out what is causing the difference between the server and client classNames.
I experienced a similar issue when adding Material-UI Chips with a delete 'x' icon. The 'x' icon rendered with a monstrous 1024px width after refreshing. The same underlying issue being that icon was not receiving the correct class for styling.
There are a few questions on Stack Overflow addressing why the client and server might render classNames differently (e.g. need to upgrade to #Material-UI/core version ^1.0.0, using a custom server.js, and using Math.random in setState), but none of these apply in my case.
I don't know enough to tell whether this Github discussion might help, but likely not since they were using a beta version of Material-UI.
Minimal steps to reproduce:
Create project folder and start Node server:
mkdir app
cd app
npm init -y
npm install react react-dom next #material-ui/core
npm run dev
edit package.json:
Add to 'scripts': "dev": "next",
app/pages/index.jsx:
import Head from "next/head"
import CssBaseline from "#material-ui/core/CssBaseline"
import SearchBar from "../components/SearchBar"
const Index = () => (
<React.Fragment>
<Head>
<link
rel="stylesheet"
href="https://fonts.googleapis.com/css?family=Roboto:300,400,500"
/>
<meta name="viewport" content="width=device-width, initial-scale=1" />
<meta charSet="utf-8" />
</Head>
<CssBaseline />
<SearchBar />
</React.Fragment>
)
export default Index
app/components/SearchBar.jsx:
import PropTypes from "prop-types"
import { withStyles } from "#material-ui/core/styles"
import TextField from "#material-ui/core/TextField"
const styles = (theme) => ({
container: {
display: "flex",
flexWrap: "wrap",
},
textField: {
margin: theme.spacing.unit / 2,
width: 200,
border: "2px solid red",
},
})
class SearchBar extends React.Component {
constructor(props) {
super(props)
this.state = { value: "" }
this.handleChange = this.handleChange.bind(this)
this.handleSubmit = this.handleSubmit.bind(this)
}
handleChange(event) {
this.setState({ value: event.target.value })
}
handleSubmit(event) {
event.preventDefault()
}
render() {
const { classes } = this.props
return (
<form
className={classes.container}
noValidate
autoComplete="off"
onSubmit={this.handleSubmit}
>
<TextField
id="search"
label="Search"
type="search"
placeholder="Search..."
className={classes.textField}
value={this.state.value}
onChange={this.handleChange}
margin="normal"
/>
</form>
)
}
}
SearchBar.propTypes = {
classes: PropTypes.object.isRequired,
}
export default withStyles(styles)(SearchBar)
Visit page in browser localhost:3000 and see this:
red border around TextField component
Refresh the browser and see this:
TextField component's styles are gone
Notice that the red border around TextField disappears.
Relevant Libs:
"react": 16.4.0
"react-dom": 16.4.0
"next": 6.0.3
"#material-ui/core": 1.2.0
The problem is the SSR rendering in Next.js, which produces the style fragment before the page is rendered.
Using Material UI and Next.js (as the author is using), adding a file called _document.js solved the problem.
Adjusted _document.js (as suggested here):
import React from 'react';
import Document, { Html, Head, Main, NextScript } from 'next/document';
import { ServerStyleSheets } from '#material-ui/styles'; // works with #material-ui/core/styles, if you prefer to use it.
import theme from '../src/theme'; // Adjust here as well
export default class MyDocument extends Document {
render() {
return (
<Html lang="en">
<Head>
{/* Not exactly required, but this is the PWA primary color */}
<meta name="theme-color" content={theme.palette.primary.main} />
</Head>
<body>
<Main />
<NextScript />
</body>
</Html>
);
}
}
// `getInitialProps` belongs to `_document` (instead of `_app`),
// it's compatible with server-side generation (SSG).
MyDocument.getInitialProps = async (ctx) => {
// Resolution order
//
// On the server:
// 1. app.getInitialProps
// 2. page.getInitialProps
// 3. document.getInitialProps
// 4. app.render
// 5. page.render
// 6. document.render
//
// On the server with error:
// 1. document.getInitialProps
// 2. app.render
// 3. page.render
// 4. document.render
//
// On the client
// 1. app.getInitialProps
// 2. page.getInitialProps
// 3. app.render
// 4. page.render
// Render app and page and get the context of the page with collected side effects.
const sheets = new ServerStyleSheets();
const originalRenderPage = ctx.renderPage;
ctx.renderPage = () =>
originalRenderPage({
enhanceApp: (App) => (props) => sheets.collect(<App {...props} />),
});
const initialProps = await Document.getInitialProps(ctx);
return {
...initialProps,
// Styles fragment is rendered after the app and page rendering finish.
styles: [...React.Children.toArray(initialProps.styles), sheets.getStyleElement()],
};
};
This problem is related to MUI using dynamic class name which contain an ID. The IDs from the server side rendered CSS are not the same as the client side CSS, hence the mismatch error. A good start is to read the MUI SSR documentation
If you have this problem with nextjs (as I did) follow the example provided by the MUI team, which can be found here: material-ui/examples/nextjs
The most important part is in "examples/nextjs/pages/_app.js":
componentDidMount() {
// Remove the server-side injected CSS.
const jssStyles = document.querySelector('#jss-server-side');
if (jssStyles) {
jssStyles.parentElement.removeChild(jssStyles);
}
}
the related ticket can be found here: mui-org/material-ui/issues/15073
what it does, is remove the server side rendered stylesheet and replace it by a new client side rendered one
The issue is the server side generates the class names but style sheets are not automatically included in the HTML. You need to explicitly extract the CSS and append it to the UI for the server side rendered components. The whole process is explained here: https://material-ui.com/guides/server-rendering/
There is one other important, separate issue here: Material UI V4 is not React Strict Mode compatible. Strict mode compatibility is slated for version 5 with the adoption of the Emotion style engine.
Until then, be sure you disable React Strict Mode. If you're using Next.js, this is turned on by default if you've created your app using create-next-app.
// next.config.js
module.exports = {
reactStrictMode: false, // or remove this line completely
}
I had the same problem with Next.js and styled component, with the transpilation by Babel. Actually, the class names are different on the client and the server side.
Fix it in writing this in your .babelrc :
{
"presets": ["next/babel"],
"plugins": [
[
"styled-components",
{ "ssr": true, "displayName": true, "preprocess": false }
]
]
}
I met this problem on Material-ui V5. The solution to fix this problem is to make sure that class name generator needs to behave identically on the server and on the client.
so adding the code below in your _app.js:
import { StylesProvider, createGenerateClassName } from '#mui/styles';
const generateClassName = createGenerateClassName({
productionPrefix: 'c',
});
export default function MyApp(props) {
return <StylesProvider generateClassName={generateClassName}>...</StylesProvider>;
}
// 1 . Warning: prop classname did not match. Material ui with React Next.js
// 2 . Use your customization css here
const useStyles = makeStyles((theme) => ({
root: {
flexGrow: 1,
},
title: {
flexGrow: 1,
},
my_examle_classssss: {
with: "100%"
}
}));
// 3 . Here my Component
const My_Example_Function = () => {
const classes = useStyles();
return (
<div className={classes.root}>
<Container>
<Examle_Component> {/* !!! Examle_Component --> MuiExamle_Component*/}
</Examle_Component>
</Container>
</div>
);
}
export default My_Example_Function
// 4. Add name parameter to the makeStyles function
const useStyles = makeStyles((theme) => ({
root: {
flexGrow: 1,
},
title: {
flexGrow: 1,
},
my_examle_classssss: {
with: "100%"
},
}), { name: "MuiExamle_ComponentiAppBar" });
{/* this is the parameter you need to add { name: "MuiExamle_ComponentiAppBar" } */ }
{/* The problem will probably be resolved if the name parameter matches the first className in the Warning: you recive..
EXAMPLE :
Warning: Prop `className` did not match.
Server: "MuiSvgIcon-root makeStyles-root-98"
Client: "MuiSvgIcon-root makeStyles-root-1"
The name parameter will be like this { name: "MuiSvgIcon" }
*/ }
I like to share this mismatching case:
next-dev.js?3515:32 Warning: Prop className did not match. Server:
"MuiButtonBase-root MuiIconButton-root PrivateSwitchBase-root-12
MuiSwitch-switchBase MuiSwitch-colorSecondary" Client:
"MuiButtonBase-root MuiIconButton-root PrivateSwitchBase-root-12
MuiSwitch-switchBase MuiSwitch-colorSecondary
PrivateSwitchBase-checked-13 Mui-checked"
On client there are two more classes which means that the behavior on client-side is different. In this case, this component shouldn't render on server-side. The solution is to dynamically render this component:
export default dynamic(() => Promise.resolve(TheComponent), { ssr: false });
I had a problem with different classNames for client and server. I was using React, Material-UI, makeStyles and SSR (server-side rendering).
The error was:
Warning: Prop `className` did not match. Server: "jss3" Client: "App-colNav-3"
I spent several hours before I figured out that I had discrepancy in webpack mode for client and server. The scripts in package.json were:
"devServer": "webpack --config webpack.server.config.js --mode=production --watch",
"devClient": "webpack --mode=development --watch",
After I changed both to have development mode, the problem was solved :)
"devServer": "webpack --config webpack.server.config.js --mode=development --watch",
"devClient": "webpack --mode=development --watch",
If somebody is still struggling even after trying above solutions, Try this
If you have used noSsr prop in any of your components or theme, then remove it.
I had the following config in mui theme object, which was causing this problem.
import { createTheme, responsiveFontSizes } from "#mui/material/styles";
let theme = createTheme({
components: {
MuiUseMediaQuery: {
defaultProps: {
noSsr: true,
},
},
},
palette: {
mode: "light",
common: {
black: "#000",
white: "#fff",
},
primary: {
main: "#131921",
contrastText: "#fff",
},
secondary: {
main: "#fb6a02",
contrastText: "#fff",
}
}
})
RemovingnoSSr fixed all of the issues in my app including style mismatch between client and server.
The problem is cause by Nextjs server side rendering. In order to solve I do as following:
Make a component to detect whether is it from Client side
import { useState, useEffect } from "react";
interface ClientOnlyProps {}
// #ts-ignore
const ClientOnly = ({ children }) => {
const [mounted, setMounted] = useState<boolean>(false);
useEffect(() => {
setMounted(true);
}, []);
return mounted ? children : null;
};
export default ClientOnly;
Wrap my page component using ClientOnly component
export default function App() {
return (
<ClientOnly>
<MyOwnPageComponent>
</ClientOnly>
);
}
So the idea is, if it is client side then only render the component on the page. Therefore if current rendering is from Client side, render <MyOwnPageComponent>, else render nothing
In my case the issue happened because of different compilation modes of webpack for client-side code and server-side: client's bundle was generated by webpack using "production" mode, while server ran some SSR code from a package optimized for "development". This created a different "className" hash in styled-components in generateAndInjectStyles():
if (process.env.NODE_ENV !== 'production') dynamicHash = phash(dynamicHash, partRule + i);
So my fix was just to align the webpack modes.
You can add the name in anywhere you use makeStyles, like this:
const useStyles = makeStyles({
card: {
backgroundColor: "#f7f7f7",
width: "33%",
},
title: {
color: "#0ab5db",
fontWeight: "bold",
},
description: {
fontSize: "1em"
}
}, { name: "MuiExample_Component" });
I am not sure how it works, but I found it here: Warning: Prop `className` did not match ~ Material UI css arbitrarily breaks on reload
I'm also using NextJS + MUI v5 and I ran into this exact error right after merging Git branches. I suspect the merge corrupted something in the cache. I deleted the contents of .next/ and restarted the dev server and the error went away.
#Leonel Sanches da Silva's answer didn't work for me, as #material-ui/styles is deprecated, but using a snippet I found for another (non-material UI) project seems to have worked just fine for me:
Hat tip to Raul Sanchez on dev.to for the answer to this one.
Next doesn't fetch styled-components styles on the server, to do that you need to add this page to pages/_document.js:
import Document from 'next/document'
import { ServerStyleSheet } from 'styled-components'
export default class MyDocument extends Document {
static async getInitialProps(ctx) {
const sheet = new ServerStyleSheet()
const originalRenderPage = ctx.renderPage
try {
ctx.renderPage = () =>
originalRenderPage({
enhanceApp: (App) => (props) =>
sheet.collectStyles(<App {...props} />),
})
const initialProps = await Document.getInitialProps(ctx)
return {
...initialProps,
styles: (
<>
{initialProps.styles}
{sheet.getStyleElement()}
</>
),
}
} finally {
sheet.seal()
}
}
}
This code may update, so check Next's styled-components example for the latest.