I am fairly new to React and still wrapping my head around custom-hooks. I cam across a code where a custom hook was created to handle the component imports.
useComponentPalette.js
import {TodoEditor} from './components/TodoEditor'
import {TodoItem} from './components/TodoItem'
import {TodoList} from './components/TodoList'
import {CheckBox} from './components/CheckBox'
const defaultComponents = {
TodoEditor,
TodoItem,
TodoList,
CheckBox
}
export function useComponentPalette(){
return defaultComponents
}
And then in order to use the hook,
const {TodoItem, TodoList, Checkbox } = useComponentPalette()
My Question :- Does this approach provides any advantage over the regular imports in the component ? or this is an anti-pattern ?
How I usually import the components is as follows
import {TodoEditor} from './components/TodoEditor'
import {TodoItem} from './components/TodoItem'
import {TodoList} from './components/TodoList'
import {CheckBox} from './components/CheckBox'
function App(){
return(
<>
<TodoList/>
</>
)
}
It's not a good idea to use react hooks like this you can get the same result without react hook
// first file name.js
import {TodoEditor} from './components/TodoEditor'
import {TodoItem} from './components/TodoItem'
import {TodoList} from './components/TodoList'
import {CheckBox} from './components/CheckBox'
export default {
TodoEditor,
TodoItem,
TodoList,
CheckBox
}
//component file
import * as Component form 'first file name';
//<Component.TodoEditor/>
//or
import {TodoEditor} form 'first file name';
The way that I use react-hooks is for making my code more dry and increase it's readability, so react-hooks is not good fit for this kind of usage.
Hi #Sachin,
In my option, React JS use hook to manage reuse stateful logic between components. In other word, Hooks do well to encapsulating state and share logic. If you want to do some stateful logic or condition base logic with these components, then it's fine with that. But if you are using just without condition in the given components. Then, This Is useless for making the custom hook. You can do that without a custom hook in a simpler way.
Here is a simple way to do that:-
In components folder. I create index file, this is the entry point of all my exporting components
In that file. I export all my components, as you can see.
I use that components like this. It much better way. In my option.
import { Header, Footer, Sider } from "./components"
before using react custom hooks, we should be aware of the rationale behind it.
Customs hooks functionality was provided to reuse stateful logic. If logic doesn't require any state, we will use simple functions and if it is about components only there there are different patterns for making code general and scaleable.
So, there is no usage of custom hook in above case at all. For me, I would go with the following code for above scenario:
// components/index.tsx
import {Todo} from './todo'
import {CheckBox} from './components/CheckBox'
export {
Todo,
CheckBox
}
// componentns/todo/index.tsx
import {Editor} from './Editor'
import {Item} from './Item'
import {List} from './List'
const Todo = {
Editor,
Item,
List
}
export default Todo;
and usage will be like
import { Checkbox, Todo } from "components"
...
<Checkbox ... />
<Todo.List ...>
<Todo.Item ... >
</Todo.Editor ... />
</Todo.Item ... >
</Todo.List>
...
P.S Usage can be different based upon the logic of components, just giving an hint how we can patterns to serve our purpose.
Hope it helps.
Related
Recently i started new project and upgraded for it libraries to newest including react. I encountered first problem when accessing passed params from dynamic route inside class component. In the past in order to do it, one would need to wrap exported class component in withRouter function returned from router. In the documentation they say that this functionality has been removed in v6 and if you need it, it can be recreated manually docs link.
I created with-router.jsx file and pasted their code:
import {
useLocation,
useNavigate,
useParams,
} from "react-router-dom";
function withRouter(Component) {
function ComponentWithRouterProp(props) {
let location = useLocation();
let navigate = useNavigate();
let params = useParams();
return (
<Component
{...props}
router={{ location, navigate, params }}
/>
);
}
return ComponentWithRouterProp;
}
next i added it to my class component:
import React, { Component } from 'react';
import withRouter from './with-router';
class Product extends Component {
render() {
return (
<div className="product">...</div>
);
}
}
export default withRouter(Product);
and it does not work, there is following error:
Compiled with problems:
WARNING in ./src/components/product.jsx 67:15-25
export 'default' (imported as 'withRouter') was not found in './with-router' (module has no exports)
so it does not seem like their own code is working, maybe someone has an idea how to make it work? another thing is to consider future implications, functionality deleted without replacement and if you need it - recreate it? why remove if you have to manually add it anyway, does not make sense with react recently.
"react": "^18.2.0"
"react-dom": "^18.2.0"
"react-router-dom": "^6.4.4"
"webpack": "^5.74.0"
"webpack-cli": "^4.10.0"
"webpack-dev-server": "^4.11.1"
As the error points out, it seems you neglected to export your custom withRouter HOC.
Compiled with problems: WARNING in ./src/components/product.jsx
67:15-25 export 'default'* (imported as 'withRouter') was not found in
'./with-router' (module has no exports*)
* Emphasis is mine
Assuming you've shared the complete with-router.jsx file contents, it's missing a default export.
import {
useLocation,
useNavigate,
useParams,
} from "react-router-dom";
function withRouter(Component) {
function ComponentWithRouterProp(props) {
const location = useLocation();
const navigate = useNavigate();
const params = useParams();
return (
<Component
{...props}
router={{ location, navigate, params }}
/>
);
}
return ComponentWithRouterProp;
}
export default withRouter; // <-- add default export!
so it does not seem like their own code is working, maybe someone has
an idea how to make it work?
The RRD code is well maintained and tested, I've not run across many blatant issues/bugs with their React hooks.
another thing is to consider future implications, functionality
deleted without replacement and if you need it - recreate it? why
remove if you have to manually add it anyway, does not make sense with
react recently.
I think it does make sense with the direction React is going.
React has made it clear that Function components and React hooks are the future of React (for now) and that Class components are, for all intents and purposes, deprecated, though they are kept around for compatibility reasons. The functionality you describe as being "deleted", i.e. removed, was replaced... by the new React hooks, and the FAQ doc you referenced is made available as a compatibility bridge if you are using current RRDv6 components with older React code. Creating this HOC is trivial, if you need it, but if the main objective is to create React function components that use React hooks then there's no need or desire for RRD to export a withRouter HOC of their own that encourages "deprecated" React component coding patterns.
A good general rule here would be to use your new withRouter component on your older class components, and for any new components you create implement them as React Function components and use the React hooks. If you want you can rewrite/convert older class components to function components, but this is basically a "only if you really need/want to" and not a "don't just convert for the sake of converting" type of thing.
I used npm init react-app appname which creates, among other files, App.js. In that file is a function component:
function App() {
return (
<SomeJSX />
);
}
I edited the function component into a class component, like so:
class App extends React.Component{
render() {
return (
<TheSameJSX />
);
}
}
Now, when I run npm start, I get an error:
Failed to compile
src/App.js
Line 4:19: 'React' is not defined no-undef
Search for the keywords to learn more about each error.
I imagine I need to add some setting somewhere that will automatically include React without me needing to explicitly import it at the top of every file. How do I do this? And why does this npm package not do that by default? I know a bit about javascript (and html and css), and have read a bit about React, but I am completely unaware of how npm or webpack works.
Thanks in advance!
EDIT: To clarify, I know how to import stuff with javascript. I can easily add import React from 'react'; to the file and make it work. However, I find it difficult to believe that adding an import statement to every single javascript file is the recommended method, and I don't understand why this example app wouldn't be set up so as to avoid having to do that. Am I mistaken? Do I really need to manually import the same thing over and over again within the same project? Could I set a global variable to React so that I can use it from wherever?
In your default function component you're not extending any classes and just writing a simple function
function App() {
return (
<SomeJSX />
);
}
In class component, you're in fact extending the Class Component by React.Component provided by React default export object and hence you must import it from the package
//only use one of these
import * as React from "react";
import {Component} from "react"; // you can directly extend without writing `React.` with this import
import React from "react"
So your code would be
import React from "react";
class App extends React.Component{
render() {
return (
<TheSameJSX />
);
}
}
Any of the above imports should be fine with a preference to the first and second one.
I am very new to Vue and I have read an article or two about it (probably vaguely).
Also, Since I have some understanding of react, I tend to assume certain things to work the same way (but probably they do not)
Anyway, I just started with Quasar and was going through the Quasar boilerplate code
In the myLayout.vue file, I see being used inside my template
<template>
<q-layout view="lHh Lpr lFf">
<q-layout-header>
<q-toolbar
color="negative"
>
<q-btn
flat
dense
round
#click="leftDrawerOpen = !leftDrawerOpen"
aria-label="Menu"
>
<q-icon name="menu" />
</q-btn>
based on my vaguely understanding, I thought for every component we are using to whom we need to pass props we need to import it as well but unfortunately I can't see it in my import-script area
<script>
import { openURL } from 'quasar'
export default {
name: 'MyLayout',
data () {
return {
leftDrawerOpen: this.$q.platform.is.desktop
}
},
methods: {
openURL
}
}
</script>
I would've thought the script to be something like
<script>
import { openURL } from 'quasar'
import {q-icon} from "quasar"
or at least something like that but here we only have
import { openURL } from 'quasar'
Also, Even if we remove the above snippet, our boilerplate app looks to be working fine so here are my two questions
Question 1: What is the use of import { openURL } from 'quasar' (like what it does)
Question 2: How can template contain <quasar-icon> or <quasar-whatever> without even importing it in script tag?
How can template contain <quasar-icon> or <quasar-whatever> without even importing it in script tag?
There are two ways to import components. The first way (which I recommend, and being most similar to React) is to import the component and add it to the components option inside the component that you want to use it within.
App.vue
<div>
<my-component/>
</div>
import MyComponent from 'my-component'
export default {
components: {
MyComponent
}
}
The second way is to import it globally for use within any Vue component in your app. You need only do this once in the entry script of your app. This is what Quasar is doing.
main.js
import Vue from 'vue'
import MyComponent from 'my-component'
Vue.component('my-component', MyComponent)
What is the use of import { openURL } from 'quasar' (like what it does)
I'm not familiar with Quasar, so I can't give you a specific answer here (I don't know what openURL does). You should check the Quasar docs.
openURL is being used as a method here. Perhaps it is being called from somewhere in the template (which you have excluded from the question).
A1) Import statement is 1 way (es6) way to split your code into different files and then import functions/objects/vars from other files or npm modules see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/import
A2) Vue allows 2 mechanisms to register components. Global and local. Globally registered components does not have to be imported and registered in every component before use (in template or render fn). See URL from comment above https://v2.vuejs.org/v2/guide/components-registration.html#Global-Registration
I am writing this question cause I would like to ask you for some help in how to use the redux on my functional components. I had a look at other examples with React components but I cannot understand how to get the "store" value in functional components.
My idea is to use my
store.getState()
To check states and interact with the UI, inside my functional component but I cannot make it happen.
Any help please ?
For example, a functional component :
import React from 'react';
import withStyles from 'isomorphic-style-loader/lib/withStyles';
import s from './Header.css';
import { Navbar, Nav } from 'react-bootstrap';
import HeaderMenu from '../HeaderMenu';
import cx from 'classnames';
function Header() {
return (
<Navbar fluid fixedTop id="Header" className={s.navContainer}>
<Nav block className={cx(s.HeaderTitle, s.hideOnSmall)}>Project title</Nav>
<HeaderMenu />
</Navbar>
);
}
export default withStyles(s)(Header);
How can I use the "store" object inside my Header component ? It works on my App component, just I don't know how to use it within my components.
My questions are:
Should I use actions for retrieving the state instead ??
Should I pass the store object component to the component properties?
Thanks in advance!
EDIT :
I am using https://github.com/kriasoft/react-starter-kit
with the redux branch https://github.com/kriasoft/react-starter-kit/tree/feature/redux
As of version 7.x react-redux now has hooks for functional components.
Header.jsx
import React from 'react';
import withStyles from 'isomorphic-style-loader/lib/withStyles';
import s from './Header.css';
import { Navbar, Nav } from 'react-bootstrap';
import HeaderMenu from '../HeaderMenu';
import cx from 'classnames';
import { useSelector } from 'react-redux'
function Header() {
const store = useSelector(store => store)
return (
<Navbar fluid fixedTop id="Header" className={s.navContainer}>
<Nav block className={cx(s.HeaderTitle, s.hideOnSmall)}>Project title</Nav>
<HeaderMenu />
</Navbar>
);
}
export default withStyles(s)(Header);
index.js
import React from 'react';
import ReactDOM from 'react-dom';
import './index.css';
import App from './App';
import { Provider } from 'react-redux'
import store from './store'
ReactDOM.render(
<Provider store={store}>
<App />
</Provider>,
document.getElementById('root')
);
As Dan Abramov mentioned in his insanely famous Egghead.io series, presentational component shouldn't be aware of Redux store and shouldn't use it directly. You should create something called container component, which will pass necessary state fields + action callbacks to your presentational component via properties.
I highly recommend to watch Dan Abramov's Egghead.io series if above concepts are not familiar to you. Patterns he is describing there are de facto standard style guide for writing React+Redux applications nowadays.
If you want to get the Redux state on a functional component, you either have to manually connect the component and Redux, which is very tedious. You would have to access the reducer variable inside your React Component, meaning import the reducer into the component file among other configurations.
This would interfere with other benefits you would normally get, such as action creators, dispatching actions automatically through middleware, and more.
A cleaner idea is to just use the Provider Component that comes with React-Redux to turn your Header component into a Container. A Container is a react component that 'listens for' any changes that have been made to the store. You are essentially wrapping your Header component in a higher order component that is connected directly to the redux store.
This way is more scalable and you can easily create a boilerplate file that can be used with any React/Redux project.
Try to understand the individual modules/components a boilerplate project contains before going with it. If you are new to react (and its complementary libraries) I recommend you start here:
https://github.com/petehunt/react-howto
For redux:
http://redux.js.org/
These are both great ressources which clarify the majority of react related questions on stackoverflow.
You can use react-redux library, and using connect you will access your store data as a component props - it's easy and efficient.
Complete newbie to React and trying to find out how to load the HTML for components rather than inserting it directly in the render method. For example
import React, {Component} from 'react';
export default class Login extends Component {
render() {
return (
<!-- how can I provide a link to the HTML template for here? -->
);
}
}
React does not have HTML. The JSX that you write in the render method is actually compiled into JavaScript. At the core, React components are all JavaScript. The styles are also inline. Componentisation is neat in React because HTML, CSS, JavaScript (interactions) are all in one place, as JavaScript.
To insert raw HTML, React has an attribute dangerouslySetInnerHTML.
<div dangerouslySetInnerHTML={createMarkup()} />
If you want some type of organization, you can use variables to set the html and then assign that to the render functionalty, but React does not use html templates
var hello = React.createClass({
render: yourVariable
});
I think you might be confused about how JSX works.Just in case, I want to clarify that JSX is what they call "syntactic sugar", that turns React methods such as React.createElement into that XML like syntax. For instance:
var Nav;
// Input (JSX):
var app = <Nav color="blue" />;
// Output (JS):
var app = React.createElement(Nav, {color:"blue"});
(from the React docs)
So, to the best of my knowledge, the JSX syntax actually belongs in the render method. If what you are really looking for is the best way to separate and reuse purely presentational code, you should read on separating your app into Container and Presentational components
https://medium.com/#learnreact/container-components-c0e67432e005#.dzjqc8yrn
https://medium.com/#dan_abramov/smart-and-dumb-components-7ca2f9a7c7d0#.mn9nf6lz6
Stateless/Presentational/Dumb Components are just functions that return JSX. So you could have your Template component:
import React from 'react';
//you need to import React to use JSX, as it will be expanded into React.createElement calls...
function Template(props){
return (
//...your template here...
);
}
And then your class
import React, {Component} from 'react';
export default class Login extends Component {
render() {
return (<Template {...props}/>);
}
}
}
Makes sense?