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https://github.com/pagarme/react-style-guide
Our React Style Guide
https://github.com/pagarme/react-style-guide
Last synced: 2 days ago
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Our React Style Guide
- Host: GitHub
- URL: https://github.com/pagarme/react-style-guide
- Owner: pagarme
- License: mit
- Created: 2017-06-28T14:04:35.000Z (over 7 years ago)
- Default Branch: master
- Last Pushed: 2023-07-12T02:39:03.000Z (over 1 year ago)
- Last Synced: 2024-05-07T06:45:14.175Z (9 months ago)
- Language: JavaScript
- Size: 121 KB
- Stars: 156
- Watchers: 144
- Forks: 47
- Open Issues: 5
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
- awesome-styleguides - https://github.com/pagarme/react-style-guide
README
# React Code Style Guide
Our React projects' best practices
# Introduction
This is meant to be a guide to help new developers understand
the React code style and best practices we adopt here at Pagar.me.
As this guide is an extension of our [JavaScript style guide][js-style-guide],
we **highly recommend** reading it before you continue.
# Installing
The rules described in this repository are also available as a NPM package.
To install the package and its dependencies:
```shell
$ npm install --save-dev [email protected] \
eslint-config-pagarme-react \
[email protected] \
stylelint-config-pagarme-react \
```
> The peer dependencies specified above have hardcoded versions.
> If you prefer, you can use the command
> `npm info eslint-config-pagarme-react@latest peerDependencies`
> to find the exact peer dependencies to install.
To include these rules into your project, create the following config files in your root folder:
> `.eslintrc`
```json
{
"extends": ["pagarme-react"],
"env": {
"browser": true
}
}
```
> `.stylelintrc`
```
{
"extends": ["stylelint-config-pagarme-react"]
}
```
# Table of contents
- [Component definition](#component-definition)
- [Project organization](#project-organization)
- [Presentational Components](#components)
- [Container Components](#containers)
- [Page Containers](#pages)
- [Formatting CSS](#formatting-css)
- [80 columns, soft tabs of 2 spaces](#80-columns-soft-tabs-of-2-spaces)
- [Camel case instead of dash-case for class names](#camel-case-instead-of-dash-case-for-class-names)
- [Never use ID and tag name as root selectors!](#never-use-id-and-tag-name-as-root-selectors)
- [When using multiple selectors, give each selector its own line](#when-using-multiple-selectors-give-each-selector-its-own-line)
- [Break lines in CSS function arguments](#break-lines-in-css-function-arguments)
- [When writing rules, be sure to](#when-writing-rules-be-sure-to)
- [Design Patterns](#css-design-patterns)
- [The parent constrains the child](#the-parent-constrains-the-child)
- [The parent doesn't assume child structure](#the-parent-doesnt-assume-child-structure)
- [Components never leak margin](#components-never-leak-margin)
- [The parent spaces the children](#the-parent-spaces-the-children)
- [Nested classes aren't for providing scope](#nested-classes-arent-for-providing-scope)
- [Variables, lots of variables!](#variables-lots-of-variables)
# Component definition
All components (presentation, containers or pages) should **always** be
defined as a directory, named with pascal casing. The main component file
should be `index.js`, main stylesheet `style.css`. CSS custom properties
can be kept in `properties.css`:
```
AwesomeCard/
├── index.js
├── properties.css
└── style.css
```
* Styles should always be defined in a separate CSS file
* Avoid prefixing or suffixing component names
- E.g.: `lib/pages/UserPage` or `lib/container/UserContainer`
* On conflict rename on import time
- `import UserContainer from '...'`
- `import { User as UserContainer } from '...'`
[:arrow_up: Back to top][table-of-contents]
# Project organization
Your project components should be separated in at least three directories:
```
awesome-react-project/
└── src/
├── components/
├── containers/
└── pages/
```
Each of these directories have special types of components:
### `components/`
Stateless components. Shouldn't store state. Most components in this
directory will be function-based components. Stuff like buttons, inputs,
labels and all presentational components goes here. This components can
also accept functions as props and dispatch events, but no state should
be held inside.
### `containers/`
Container components can store state. Containers are built mostly from
the composition of presentational components with some styles to layout
them together. Containers can also store internal state and access refs
to provide additional logic, but all actions should be accepted as
component callbacks.
### `pages/`
Page components can store state, receive route parameters and dispatch
Redux actions when applicable. Pages are the highest level of application's
components. They represent the application routes and most times are
displayed by a router. Pages are also responsible for handling container
components callbacks and flowing data into children containers.
[:arrow_up: Back to top][table-of-contents]
# Code standards
## Destruct your `props`
### More than 2 props from an object been used in the same place should be destructed
## Code style
### Line length should not exceed 80 characters.
### Use explanatory variables
Bad
```js
const onlyNumbersRegex = /^\d+$/
const validateNumber = message => value => !onlyNumbersRegex.test(value) && message
validateNumber('error message')(1)
```
Good
```js
const onlyNumbersRegex = /^\d+$/
const getNumberValidation = message => value => !onlyNumbersRegex.test(value) && message
const isNumber = getNumberValidation('error message')
isNumber(1)
```
### Use searchable names
Bad
```js
setTimeout(doSomething, 86400000)
```
Good
```js
const DAY_IN_MILLISECONDS = 86400000
setTimeout(doSomething, DAY_IN_MILLISECONDS)
```
## Naming
### Test files must start with the class which will be tested followed by `.test`.
### Class and components folders names must start with capital letter.
## React peculiarities
### Never "promisify" the `setState`
It's a small anti-pattern which can cause some problems in the component lifecicle. You can found more arguments about this in [this issue](https://github.com/facebook/react/issues/2642#issuecomment-352135607)
## Mixins
- [Do not use mixins](https://reactjs.org/blog/2016/07/13/mixins-considered-harmful.html)
Why? Mixins introduce implicit dependencies, cause name clashes, and cause snowballing complexity. Most use cases for mixins can be accomplished in better ways via components, higher-order components, or utility modules.
## Components
### One line props when are more than 2 or big props
Bad
```jsx
null} className="aLongSpecificClassName">
Click here
Click here
Click here
```
Good
```jsx
null}
type="submit"
>
Click here
```
### One line component
Bad
``` js
Bad example
```
Good
``` js
Bad
example
```
# CSS are modules!
We use CSS modules everywhere. CSS modules are great because they provide
scope to CSS and allow us to create compartmentalized styles that don't
leak to global scope. Here are our good practices of doing CSS modules:
## Formatting CSS
### 80 columns, soft tabs of 2 spaces
Keep your code lines under 80 columns wide. This helps when opening multiple splits.
Use soft tabs of 2 spaces to save some space! :stuck_out_tongue:
### Camel case instead of dash-case for class names
With CSS modules, camel case makes much more sense:
GOOD
lib/components/Input/index.js
lib/components/Input/style.css
```js
import style from './style.css'
const Item = ({ children }) =>
{children}
export default Item
```
```css
.circleBullet {
list-style-type: disc;
}
```
[:arrow_up: Back to top][table-of-contents]
### Never use ID and tag name as root selectors!
Using ID and tag name at the selector's root makes the rule to be applied
globally.
GOOD
lib/components/Item/index.js
lib/components/Item/style.css
```js
import style from './style.css'
const Item = ({ title, thumbnail }) =>
export default Item
```
```css
.container > img {
background-color: #CCCCCC;
}
```
BAD
lib/components/Item/index.js
lib/components/Item/style.css
```js
import style from './style.css'
const Item = ({ title, thumbnail }) =>
export default Item
```
```css
img {
background-color: #CCCCCC;
}
```
[:arrow_up: Back to top][table-of-contents]
### When using multiple selectors, give each selector its own line
Organize one selector per line, even when placing all of them at the same line doesn't
exceed 80 columns.
GOOD
BAD
```css
.container > img,
.container > div,
.container > section {
background-color: #CCCCCC;
}
```
```css
.container > img, .container > div, .container > section {
background-color: #CCCCCC;
}
```
[:arrow_up: Back to top][table-of-contents]
### Break lines in CSS function arguments
Sometimes, not to exceed the 80 columns limit, you need to break lines. While at it, be sure to do it right after the colon, and keep at one argument per line.
GOOD
BAD
```css
.container {
background-color:
linear-gradient(
0deg,
var(--color-light-yellow-12),
var(--color-light-yellow-10),
);
}
```
```css
.container {
background-color: linear-gradient(0deg, --color-light...
}
.container {
background-color: linear-gradient(
0deg, var(--color-light-yellow-12), var(--color-lig...
}
```
[:arrow_up: Back to top][table-of-contents]
### When writing rules, be sure to
* Put a space before the opening brace `{`
* In properties put a space after (but not before) the `:` character
* Put closing braces `}` of rule declarations on a new line
* Leave **ONE** blank line in between rule declarations
GOOD
BAD
```css
.container {
font-size: 12pt;
}
.thumbnail {
width: 160px;
height: 90px;
}
```
```css
.container{
font-size:12pt;}
.thumbnail{
width:160px;
height:90px;}
```
[:arrow_up: Back to top][table-of-contents]
## CSS Design Patterns
### The parent constrains the child
Leaf components shouldn't constrain width or height (unless it makes
sense). That said, most components should default to fill the parent:
GOOD
lib/components/Input/index.js
lib/components/Input/style.css
```js
import style from './style.css'
const Input = ({ children }) =>
{children}
export default Input
```
```css
.input {
box-sizing: border-box;
padding: 10px;
width: 100%;
}
```
[:arrow_up: Back to top][table-of-contents]
### The parent doesn't assume the child's structure
Sometimes we don't want to fill the whole width by default. An example is
the button component, which we want to resize itself based on title width.
In this cases, we should allow the parent component to inject styles into
the child component's container. The child is responsible for choosing where
parent styles are injected.
For merging styles, always use [`classnames`][classnames] package. The
rightmost arguments overrides the leftmost ones.
GOOD
lib/components/Button/index.js
lib/components/Button/style.css
```js
import classNames from 'classnames'
import style from './style.css'
const Button = ({ children, className }) =>
{children}
export default Button
```
```css
.button {
box-sizing: border-box;
padding: 10px;
width: 100%;
}
```
[:arrow_up: Back to top][table-of-contents]
### Components never leak margin
All components are self-contained and their final size should never suffer
margin leakage! This allows the components to be much more reusable!
BAD
GOOD
```
|--|-content size-|--| margin
____________________
| ______________ | | margin
| | | |
| | | |
| | | |
| |______________| |
|____________________| | margin
|---container size---|
```
```
|-content size-|
______________
| |
| |
| |
|______________|
```
[:arrow_up: Back to top][table-of-contents]
### The parent spaces the children
When building lists or grids:
* Build list/grid items as separate components
* Use the the list/grid container to space children
* To space them horizontally, use `margin-left`
* To space them vertically, use `margin-top`
* Select the `first-child` to reset margins
GOOD
lib/containers/Reviews/index.js
lib/containers/Reviews/style.css
```js
import style from './style.css'
const Reviews = ({ items }) =>
{items.map(item =>
)}
export default Reviews
```
```css
.container > img {
margin-left: 10px;
}
.container > img:first-child {
margin-left: unset;
}
```
[:arrow_up: Back to top][table-of-contents]
### Nested classes aren't for providing scope
CSS modules already provides us scope. We don't need to use nested classes
for providing scope isolation. Use nested class selectors for modifying
children based on parent class. A use case is when a component is in
error or success state:
BAD
lib/components/Button/index.js
lib/components/Button/style.css
```js
import style from './style.css'
const Button = ({ children }) =>
{children}
export default Button
```
```css
.button {
box-sizing: border-box;
padding: 10px;
width: 100%;
}
.button .icon {
width: 22px;
height: 22px;
}
```
GOOD
lib/components/Input/index.js
lib/components/Input/style.css
```js
import style from './style.css'
const Input = ({ value, onChange, error }) =>
{error}
export default Input
```
```css
.error p {
color: red;
display: unset;
}
```
[:arrow_up: Back to top][table-of-contents]
### Variables, lots of variables!
We encourage the "variabilification". Always define variables to increase
reuse and make styles more consistent. The CSS4 specification defines a way
to declare native variables. We adopted them as the standard.
To define a variable accessible globally:
GOOD
app/App/variables.css
app/components/Button/styles.css
```css
:root {
--color-green-1: #6CCFAE;
--color-green-2: #6B66B5;
--color-green-3: #AAC257;
--color-green-4: #68B5C1;
}
```
```css
.container {
background-color:
linear-gradient(
0deg,
var(--color-green-1),
var(--color-green-2)
);
}
```
[:arrow_up: Back to top][table-of-contents]
---
[table-of-contents]: #table-of-contents
[classnames]: https://www.npmjs.com/package/classnames
[js-style-guide]: https://github.com/pagarme/javascript-style-guide