Découvrez Material-UI - votre nouvelle bibliothèque d'interface utilisateur préférée

Mise à jour (17/05/2018): Material-UI v1.0.0 est sorti! Découvrez ce post d'Olivier.

Hein? Encore une autre bibliothèque? Quel est le problème avec Bootstrap? Et pourquoi pas la v0.20?

Bonnes questions! Commençons par une brève introduction. En un mot, Material-UI est un projet open-source qui comprend des composants React qui implémentent la conception matérielle de Google.

Il a démarré en 2014, peu de temps après la sortie de React au public, et sa popularité n'a cessé de croître. Avec plus de 35 000 étoiles sur GitHub, Material-UI est l'une des meilleures bibliothèques d'interface utilisateur pour React.

Son succès n'est cependant pas venu sans défis. Conçu avec LESS, Material-UI v0.x était sujet aux pièges CSS courants, tels que la portée globale, qui conduisent le projet sur la trajectoire CSS-in-JS. C'est ainsi que nexts'est produit en 2016.

Le voyage vers un meilleur style, comme le dit Olivier Tassinari, a commencé avec des styles en ligne, mais leurs performances sous-optimales et leur prise en charge limitée des fonctionnalités (pensez aux pseudo sélecteurs ou aux requêtes multimédias) ont finalement fait la transition de l'équipe vers JSS. Et le garçon ont-ils fait un choix judicieux.

Quel est le battage médiatique avec la version v1?

C'est mauvais. Non seulement il résout les problèmes inhérents à LESS, mais il déverrouille également une tonne de fonctionnalités formidables, y compris

  • styles dynamiques générés lors de l'exécution
  • thèmes imbriqués avec remplacements intuitifs
  • temps de chargement réduit grâce à la division du code

Et beaucoup plus. La bibliothèque est également suffisamment mature pour être utilisée en production À tel point que l'équipe suggère la v1 pour tous les nouveaux projets à venir.

D'accord, allons-nous créer une application, ou quoi?

Heureux que vous ayez demandé! Pour cette démo, nous allons créer une application de fitness simple. De toute façon, tout le monde s'ennuie des applications à faire, non?

La lecture est géniale et tout, mais regarder est souvent plus amusant! Découvrez cette playlist que j'ai créée sur YouTube si vous souhaitez créer une application plus avancée.

Ok, tu m'as convaincu. Comment commencer?

Nous allons d'abord démarrer notre application avec create-react-app

create-react-app mui-fitnesscd mui-fitnesscode .

Et qu'en est-il de Material-UI?

Si vous avez du fil, l'installation est aussi simple que

yarn add @material-ui/core

Sinon, avec npm

npm i @material-ui/core

Il n'y a pas si longtemps, nous spécifions @nexttag pour extraire la dernière pré-version (par exemple, cela aurait pu ressembler à v1.0.0-beta.47). Maintenant que la v1 et la v0.x sont sous la material-uiportée, nous devons référencer le cœur de la bibliothèque avec /corepour cibler la dernière version. Ne manquez pas cette dernière partie, sinon vous vous retrouverez avec la 0.20dépendance stable !

Attendez, est-ce vraiment ça?

Presque! Une dernière chose est les polices. Nous allons utiliser la police Roboto recommandée du CDN de Google:

Vous pouvez également le récupérer depuis NPM avec

yarn add typeface-roboto# or npm i typeface-roboto

dans ce cas, vous devrez avoir une importation à la racine de votre projet

// Make sure you only load 300, 400, & 500 font weights though!import 'typeface-roboto'

Terminé! Que dois-je faire ensuite?

Eh bien, refactorisons notre App.jscomposant avant d'aller plus loin

import React, { Component } from 'react'
export default class App extends Component { state = { exercises: [], title: '' }
 render() { return 

Exercises

}}

Et pourquoi ne pas nettoyer index.jspendant que nous y sommes?

import React from 'react'import { render } from 'react-dom'import App from './App'
render(, document.getElementById('root'))

N'hésitez pas à supprimer les fichiers restants ci-dessous src, car nous n'en aurons pas besoin.

D'où vient Material-UI?

Assez juste, il est temps de le voir en action. Changeons le laid h1en une belle Typographyrubrique:

import Typography from '@material-ui/core/Typography'
...
 render() { return (  Exercises  ) }}
Notez que depuis la v1.0.0-rc.0, MUI a été déplacé vers @material-ui/coreet le chemin d'importation a été aplati. C'était le dernier changement de rupture dans la pré-version.

Alors vas-y et cours yarn startpour voir la magie.

Nous sommes sur un bon départ! TypographyLe composant est livré avec un ensemble prédéfini de tailles de caractères. D' autres variants comprennent body1, title, display2et ainsi de suite. Parmi les autres accessoires intégrés, alignnous utilisons ici pour centrer le texte horizontalement et gutterBottomqui ajoute une marge inférieure.

Why don’t we expand this to a form, so we can create our own exercises? We’ll start with a TextField and bind it to the title on the state

import Typography from '@material-ui/core/Typography'import TextField from '@material-ui/core/TextField'
...
 handleChange = ({ target: { name, value } }) => this.setState({ [name]: value })
 render() { const { title } = this.state return ( ...    ) }}

Of course, we’d need to make React happy by wrapping Typography and form with a parent element. What could be a better opportunity for a paper-sheet card-like background? Let’s reach out to Paper then

import Paper from '@material-ui/core/Paper'
...
 render() { const { title } = this.state return  ...  } }}

It’s also about time to start using named imports (assuming our Webpack setup allows for tree shaking):

import { Paper, Typography, TextField } from '@material-ui/core'

Sweet! And what good is a form without the submit button? Buttons are a staple component in Material-UI; you’ll see them everywhere. For instance,

import { Paper, Typography, TextField, Button } from '@material-ui/core'...  Create    }}

It should read well. type is a regular React prop, color and variant are Material-UI-specific, and make up a rectangle-shaped button. Another variant would be fab for a floating button, for example.

It doesn’t do much though. We’ll have to intercept the form submit event

 return  ...  ...   }}

and then handle it with

 handleCreate = e => { e.preventDefault()
 if (this.state.title) { this.setState(({ exercises, title }) => ({ exercises: [ ...exercises, { title, id: Date.now() } ], title: '' })) } }

Whoa! What’s that cryptic code all about? Very quickly, we

  1. Prevent the default page reload
  2. Check if the title field is non-empty
  3. Set the state with an updater function to mitigate async updates
  4. Destructure exercises and title off the prevState object
  5. Spread out the exercises on the next state with a new exercise object
  6. Reset the title to clear out the input field

Guess I should have mentioned that I’m in love with ES6 too. Aren’t we all?

But how do we list them?

Now is the right time to. Is there a list component? Of course, you silly goose!

Inside a List, we’ll loop through our exercises and return a ListItem with some ListItemText for each

import { List, ListItem, ListItemText } from '@material-ui/core'
...
 render() { const { title, exercises } = this.state return  ...  {exercises.map(({ id, title }) =>    )}   }}

Let’s also hard-code a few initial exercises to get something on the screen. You guessed it, the trinity of all weight lifting workouts, ladies and gents:

 state = { exercises: [ { id: 1, title: 'Bench Press' }, { id: 2, title: 'Deadlift' }, { id: 3, title: 'Squats' } ], title: '' }

Last but not least, our users are likely to make typos, so we better add a delete button next to each exercise, so they could remove entries they no longer want in their list.

We can use ListItemSecondaryAction to do exactly that. Placed on the far right of the list item, it can hold a secondary control element, such as an IconButton with some action

import { /*...*/, ListItemSecondaryAction, IconButton} from '@material-ui/core'
...
     this.handleDelete(id)} > {/* ??? */}   
...

And let’s not forget the delete handler as well:

 handleDelete = id => this.setState(({ exercises }) => ({ exercises: exercises.filter(ex => ex.id !== id) }))

which will simply filter our exercises down to those that don’t match the id of the one that needs to be removed.

Can we have a trash bin icon inside the button?

Yes, that would be great! Though you could use Material Icons from Google’s CDN directly with either Icon or SvgIcon components, it’s often preferable to go with a ready-made preset.

Luckily, there’s a Material-UI package for those

yarn add @material-ui/icons# or npm i @material-ui/icons

It exports 900+ official material icons as React components, and the icon names are nearly identical, as you’ll see below.

Let’s say we wanted to add a trash icon. We’d first head over to material.io/icons to find out its precise name

Then, we turn that name into PascalCase in our import path

import Delete from '@material-ui/icons/Delete'

Just like with Material-UI components, if your setup has tree-shaking enabled, you could shorten the import to

import { Delete } from '@material-ui/icons'

which is especially useful when importing several icons at once.

Now that we have our trash icon, let’s display it inside our delete button

 this.handleDelete(id)}>

How can I make the form look less ugly?

Ah, styling. I thought you’d never ask! A gentle touch of CSS wouldn’t hurt. So then, do we import an external stylesheet with global styles? Or, perhaps, use CSS modules and assign scoped class names to our elements? Not quite.

Under the hood, Material-UI forks a CSS-in-JS library known as react-jss.

It’s a React integration of the JSS library by the same author, Oleg Isonen. Remember we touched on it in the beginning? Its basic idea is to enable you to define styles in JavaScript. What makes JSS stand out among other libs though, is its support for SSR, small bundle size, and rich plugin support.

Essayons! Dans notre Appcomposant, créez un objet de styles comme vous le feriez avec des styles en ligne. Ensuite, trouvez une clé, par exemple root, faisant référence à l' Paperélément racine , et écrivez quelques styles dans camelCase

const styles = { root: { margin: 20, padding: 20, maxWidth: 400 }}

Ensuite, importez withStylesHOC depuismaterial-ui

import { withStyles } from '@material-ui/core/styles'

et envelopper le Appcomposant avec lui, en passant l' stylesobjet comme argument

export default withStyles(styles)( class App extends Component { ... })
Notez que vous pouvez également utiliser withStylesHOC comme décorateur. Gardez à l'esprit que create-react-react ne prend pas encore en charge les décorateurs prêts à l'emploi, donc si vous insistez pour les utiliser, vous devrez les éjecter ou les bifurquer pour modifier la configuration.

Cela injectera un classesaccessoire dans Appcontenant un nom de classe généré dynamiquement pour notre rootélément

The class name is guaranteed to be unique, and it will often be shortened in a production build. We then assign it to Paper via className attribute

 render() { const { title, exercises } = this.state const { classes } = this.props
 return  ...  }

How does this magic work? Turns out, withStyles is responsible for the dirty work. Behind the scenes, it injected an array of styles into the DOM under le> tags. You could spot them if you dig into the with dev tools

Original text


You could also see other style tags related to native components, such as MuiListItem for the ListItem component we imported earlier. Those are auto-injected on demand, for each given UI element that you import.

That means that Material-UI will never load any styles for the components that we don’t use. Hence, increased performance and faster load times. This is very different from Bootstrap, which requires loading the entire monolithic CSS bundle, whether you happen to use its vast assortment of classes or not.

Let’s also style the form so it looks neat

const styles = { root: { ... }, form: { display: 'flex', alignItems: 'baseline', justifyContent: 'space-evenly' }}

This will make the text field and the button nicely spaced out. Feel free to refer to align-items and justify-content at CSS-Tricks should you need any further clarification on the Flexbox layout.

Sure, but what’s up with theming then?

withStyles HOC is tailored for customizing a one-off component, but it’s not suited for application-wide overwrites. Whenever you need to apply global changes to all components in Material-UI, your first instinct would be to reach out to the theme object.

Themes are designed to control colors, spacing, shadows, and other style attributes of your UI elements. Material-UI comes with built-in light and dark theme types, light being the default.

If we turn our styles into an anonymous function, it will receive the theme object as an arg, so we can inspect it

const styles = theme => console.log(theme) || ({ root: ..., form: ...})

The way you customize your theme is through configuration variables, like palette, type, typography, etc. To have a closer look at all the nested properties and options, visit the Default Theme section of the Material-UI docs.

Let’s say we wanted to change the primary color from blue to orange. First off, we need to create a theme with createMuiTheme helper in index.js

import { createMuiTheme } from '@material-ui/core/styles'
const theme = createMuiTheme({ /* config */ })

In Material-UI, colors are defined under the palette property of theme. The color palette is subdivided into intentions which include primary, secondary, and error. To customize an intention, you can simply provide a color object

import { orange } from '@material-ui/core/colors'
const theme = createMuiTheme({ palette: { primary: orange }})

When applied, the color will then be calculated for light, main, dark, and contrastText variations. For more granular control though, you could pass in a plain object with any of those four keys

const theme = createMuiTheme({ palette: { primary: { light: orange[200] // same as '#FFCC80', main: '#FB8C00', // same as orange[600] dark: '#EF6C00', contrastText: 'rgb(0,0,0)' } }})

As you can see, individual colors can be expressed as both a hex or rgba string (#FFCC80) and a hue/shade pair (orange[200]).

Creating a theme on its own won’t suffice. To overwrite the default theme, we would need to position MuiThemeProvider at the root of our app and pass our custom theme as a prop

import { /*...*/, MuiThemeProvider } from '@material-ui/core/styles'
const theme = createMuiTheme({ palette: { primary: orange }})
render(   , document.getElementById('root'))

MuiThemeProvider will then pass down the theme to all its child elements through React context.

Though it may seem like a lot of work to change a color, keep in mind that this overwrite will propagate to all components nested under the provider. And apart from colors, we can now fine-tune viewport sizes, spacing, opacity, and many other parameters.

Utilizing config variables when styling your components will aid with consistency and symmetry in your app’s UI. For example, instead of hard-coding magic values for margin and padding on our Paper component, we could instead rely on the spacing unit off the theme

const styles = ({ spacing: { unit } }) => ({ root: { margin: unit, padding: unit * 3, maxWidth: 400 }, form: ...}

theme.spacing.unit comes at 8px by default, but if it’s used uniformly across the app, when we need to update its value, rather than scavenging across the entire codebase, we only need to change it in one place, that is, in our options object that we pass to createMuiTheme.

Theme variables are plentiful, and if you run into a use case that’s not covered by the built-in theme object, you could always define your own custom vars. Here’s a slightly modified version of our fitness app that showcases color palette, theme type, and spacing unit options

Note that the example above is only a demo. It re-creates a new theme each time an option changes, which leads to a new CSS object being re-computed and re-injected into the DOM. Most often than not, your theme config will remain static.

There are far more interesting features that we haven’t covered. For example, Material-UI comes with an opt-in CssBaseline component that applies cross-browser normalizations, such as resetting margins or font family (very much like normalize.css does).

As far as components go, we have our standard Grid with a 12-column layout and five viewports (xs, sm, md, lg, and xl). We’ve also got familiar components like Dialog, Menu, and Tabs, as well as elements, such as Chip and Tooltip. Indeed, there’s a whole slue of others, and fortunately, they are all very-well documented with runnable demo code from CodeSandbox

Aside from that, Material-UI Next also works with SSR, if you’re into that. Besides, although it comes with JSS out of the box, it can me made to work with just about any other library, like Styled Components, or even raw CSS.

Be sure to check out the official docs for more info.

I hope you found this read useful! And if you like it so much that you are excited to learn more about Material-UI or React, then check out my YouTube channel maybe?

Thanks for stopping by! And big thanks to the team over at Call-Em-All and all the backers who helped to build this awesome library ❤️

Cheers,

Alex