Unidirectional Data Flow in React with MobX - javascript

I'm trying to setup a project architecture using MobX and React and was wondering if doing this following would be considered "not bad". I don't want this question to end up being another "this is a matter of personal preference and so this question doesn't belong here... We can all agree that some things really are bad.
So I'm thinking of only having a single Store.js file that looks something like this:
import { observable, action, useStrict } from 'mobx';
useStrict(true);
export const state = observable({
title: ''
});
export const actions = {
setTitle: action((title) => {
state.title = title;
})
};
Note: that all application state will be in state, there will only be a single store.
I then use state in my root component a.k.a App.js like so:
import React, { Component } from 'react';
import { observer } from 'mobx-react';
import { state } from './Store';
import DisplayTitle from './components/DisplayTitle/DisplayTitle';
import SetTitle from './components/SetTitle/SetTitle';
class App extends Component {
render() {
return (
<div className="App">
<DisplayTitle title={state.title}/>
<SetTitle />
</div>
);
}
}
export default observer(App);
I'll obviously have a whole bunch of components in my app, but none of the components will ever read state directly from Store.js. Only my App.js will import the state and pass it down the component tree.
Another note: I'm not so sure anymore why other components can't read the state directly from Store.js...
This is the case with the DisplayTitle component:
import React, { Component } from 'react';
class DisplayTitle extends Component {
render () {
return (
<h1>{this.props.title}</h1>
);
}
}
export default DisplayTitle;
But, even though no other components can directly import state (except App.js), any component can import actions from Store.js in order to mutate the state.
For example in the SetTitle component:
import React, { Component } from 'react';
import { actions } from './../../Store';
class SetTitle extends Component {
updateTitle (e) {
actions.setTitle(e.currentTarget.value);
}
render () {
return (
<input onChange={this.updateTitle} type='text'/>
);
}
}
export default SetTitle;
Are there any flaws or other obvious reasons why this approach wouldn't be the best route to go? I'd love any and all feedback!

you are missing a few things
at root level:
import { Provider } from 'mobx-react'
...
<Provider state={state}>
<Other stuff />
</Provider>
At component level:
import { inject } from 'mobx-react'
#inject('state')
class Foo ... {
handleClick(){
this.props.state.setTitle('foo')
}
render(){
return <div onClick={() => this.handleClick()}>{this.props.state.title}</div>
}
}
You can stick only the interface actions={actions} in your provider and inject that, ensuring children can call your API methods to mutate state and have it flow from bottom up. Though if you were to mutate it direct, no side effects will happen because all components willReact and update in your render tree - flux is cleaner to reason about.

Related

Pass state from App.js to React Router component

I have a state in App.js that gets populated with animal data returned by an API. This data is accessible with this.state.animals on the component that is loaded, but my problem is when changing routes to /animals, I can no longer call this.state.animals. It's as if I no longer have access or the data is gone. How can I pass the state to any component when I navigate to them?
App.js
import React, { Component } from 'react';
import { BrowserRouter as Router, Route, NavLink } from 'react-router-dom'
import Animals from './components/Animals'
class App extends Component {
state = {
animals: []
}
componentDidMount() {
fetch('animals api path here')
.then(result => result.json())
.then((data) => {
this.setState({ animals: data })
})
.catch(console.log)
}
render() {
return (
<Router>
<NavLink to="/animals">animals</NavLink>
<Route exact path="/animals" render={()=> <Animals parentState={this.state.animals} />} />
</Router>
);
}
}
export default App
components/Animals.js
import React, { Component } from 'react'
class Animals extends Component {
render() {
console.log(this.state.animals)
return (
<h2>Animals</h2>
//<div>I would loop through and list the animals if I could...</div>
)
}
}
export default Animals
In this example if you want to access animal data, it would be {this.props.parentState} inside fo the animal component
Your Route declaration is defined outside the context of the router. When using React-Router, all your components should have among their ancestors a . Usually, is the top-level component rendered in (at least if you are not using other libraries that need root-context definition, like Redux).

How push route to another path in react-redux connected component

i wan't to make conditional routing in my component. I'm using react-redux. I have tried different things like but getting undefined error.
this.props.history.push('/pathname')
so what i wan't to do, on component will mount i'm checking some boolean value from my redux state if this value will return false i want to redirect user to another route.
my component is:
import React, {Component} from 'react'
import { connect } from 'react-redux';
import { bindActionCreators } from 'redux'
class SomeComponent extends Component {
componentWillMount() {
this.props.someFunc()
if ( this.props.userLogin[0].isUserLogin === false ) {
/// here i want to redirect to another route
}
}
render() {
return(
<div>Some Content</div>
)
}
}
const mapStateToProps = state => ({
userLogin: state.UserLogin,
})
function mapDispatchToProps(dispatch) {
return {
someFunc: bindActionCreators(someAction, dispatch)
}
}
export default connect(mapStateToProps, mapDispatchToProps)(SomeComponent)
Like in example i want to redirect in component will mount user to another path. How i can do that?
You need Redirect
import {Redirect} from 'react-router-dom';
{boolFlag && <Redirect to="/hello" />} // put this in render
Do you mean "history is undefined"?
You can get history from parent component

React Router & Global Context

I'm building an e-commerce website with React (my first ever React project) and I'm using React router to manage my pages.
I've got the following component tree structure:
<Router>
<BrowserRouter>
<Router>
<withRouter(Base)>
<Route>
<Base>
<BaseProvider>
<Context.Provider>
<Header>
<PageContent>
The standard React Router structure basically, and withRouter I've got the following:
Base.js
import React, { Component } from 'react';
import { withRouter } from 'react-router';
import { Header } from './Header';
import { Footer } from './Footer';
import Provider from '../../BaseProvider';
class Base extends Component {
render() {
return (
<Provider>
<Header/>
<div className="container">{this.props.children}</div>
<Footer />
</Provider>
);
}
}
BaseProvider.js
import React, { Component, createContext } from 'react';
const Context = createContext();
const { Provider, Consumer } = Context;
class BaseProvider extends Component {
state = {
cart: [],
basketTotal: 0,
priceTotal: 0,
};
addProductToCart = product => {
const cart = { ...this.state.cart };
cart[product.id] = product;
this.setState({ cart, basketTotal: Object.keys(cart).length });
};
render() {
return (
<Provider
value={{ state: this.state, addProductToCart: this.addProductToCart }}
>
{this.props.children}
</Provider>
);
}
}
export { Consumer };
export default BaseProvider;
This gives me a template essentially, so I just the children pages without having to include Header and Footer each time.
If I want to use my global context I'm having to import it each time, and it seems like I've done something wrong as surely I should be able to use this on any page since it's exported in BaseProvider?
If I was to visit the About page, I'd get the same component structure, but no access to the consumer without using:
import { Consumer } from '../../BaseProvider';
Why do I have to do this for each file even though it's exported and at the top level of my BaseProvider? It just seems such a bad pattern that I'd have to import it into about 20 files...
Without importing it, I just get:
Line 67: 'Consumer' is not defined no-undef
I tried just adding the contextType to base but I get: Warning: withRouter(Base): Function components do not support contextType.
Base.contextType = Consumer;
I feel like I've just implemented this wrong as surely this pattern should work a lot better.
I'd recommend using a Higher Order Component - a component that wraps other components with additional state or functionality.
const CartConsumer = Component => {
return class extends React.Component {
render() {
return (
<MyContext.Consumer>
<Component />
</MyContext.Consumer>
)
}
}
}
Then in any component where you'd like to use it, simply wrap in the export statement:
export default CartConsumer(ComponentWithContext)
This does not avoid importing completely, but it's far more minimal than using the consumer directly.

MobX + React Native : way to inject stores

I'm trying to work with MobX for a new project.
I started it on May 2017, and everything was working well. I had to stop, and now I go on developing it. I had to make an npm install to manage making it working, but now, I have some problem with stores...
I rely on this tutorial for the structure : https://blog.callstack.io/write-react-native-apps-in-2017-style-with-mobx-e2dffc209fcb
This is my structure :
Main index.js
import { Provider } from 'mobx-react';
import Stack from './router';
import stores from './stores';
export default class App extends Component {
render() {
return (
<Provider {...stores}>
<Stack />
</Provider>
);
}
}
Index.js of my stores in ./stores/index.js
import ChatStore from './ChatStore';
import UserStore from './UserStore';
export default {
UserStore: new UserStore(),
ChatStore: new ChatStore(),
};
./stores/UserStore.js (important parts)
import { observer, inject } from 'mobx-react';
import {autobind} from 'core-decorators';
...
#inject(['ChatStore'])
#observer
#autobind
export default class UserStore {
#observable isAuthenticated = false;
#observable isConnecting = false;
#observable user = null;
#observable messages = [];
#observable hasMoreMessages = false;
#observable skip = 0;
...
login() {
const payload = {
strategy: 'local',
material_id: DeviceInfo.getManufacturer(),
password: DeviceInfo.getManufacturer()
};
return this.authenticate(payload);
}
...
Now, for components part :
Router.js
import { StackNavigator } from 'react-navigation';
import Home from './containers/Home';
const stackNavigatorConfig = {
initialRouteName: 'Home',
};
export default StackNavigator({
Home: {
screen: Home,
},
}, stackNavigatorConfig);
./containers/Home.js
import React, { Component } from 'react';
import { AsyncStorage } from 'react-native';
import { observable } from 'mobx';
import { observer, inject } from 'mobx-react';
#inject('UserStore')
#observer
export default class Home extends Component {
props: Props;
...
render() {
this.props.UserStore.login().catch(error => {
console.log('LOGIN', 'ERROR', JSON.stringify(error), error.message);
});
return {
...
}
}
And then, I get an error :
So, I sum up :
I use <Provider> from MobX, to give all my stores to my app
Then, I get the Store I want in my component with #inject
I use it as a props, using this.props.UserStore...
But it does not work. I rely on this tutorial for the structure : https://blog.callstack.io/write-react-native-apps-in-2017-style-with-mobx-e2dffc209fcb
Maybe there was an update between May 2017 and today, that makes things different... It was working well on May 2017.
I think this is a dummy error, but I can't find which one...
Everything looks good except the decorators on your UserStore class: #inject(['ChatStore']) #observer #autobind. #inject(['ChatStore']) #observer is used on React components, #autobind might still work as intended.
It should work if you remove those.
maybe worth using #action from mobx

Redux: Single container, multiple components

I'm quite new to both React and Redux, and I'm unsure about both best practices and technical solution to a case I'm working on. I'm using "component" and "container" as defined by Dan Abramov here.
The component I'm working on is a small collection of filter components: One input text field and two buttons, all filtering a list of entities. I've tried two approaches:
First approach: Single component containing three instances of two types of containers, containers connected to corresponding components.
This was what I first made. Here, the root component looks like the following:
import React, { PropTypes, Component } from 'react';
import Config from '../../config';
import FilterInput from '../containers/FilterInput';
import FilterLink from '../containers/FilterLink'
class FilterController extends Component {
render() {
return (
<div className='filterController'>
<FilterInput displayName="Search" filterName={Config.filters.WITH_TEXT} />
<FilterLink displayName="Today" filterName={Config.filters.IS_TODAY} />
<FilterLink displayName="On TV" filterName={Config.filters.ON_TV} />
</div>
)
}
}
export default FilterController;
The two containers referenced here look pretty much as expected, as do the connected components. I'll show the FilterLink as an example:
import React, { PropTypes, Component } from 'react';
import {connect} from 'react-redux';
import {toggleFilter} from '../actions';
import FilterButton from '../components/filterbutton'
const mapStateToProps = (state, ownProps) => {
return {
active: !!state.program.filters[ownProps.filterName]
}
}
const mapDispatchToProps = (dispatch, ownProps) => {
return {
onClick: () => {
dispatch(toggleFilter(ownProps.filterName, ownProps.input))
}
}
}
const FilterLink = connect(
mapStateToProps,
mapDispatchToProps
)(FilterButton)
export default FilterLink
And the corresponding FilterButton component:
import React, { PropTypes, Component } from 'react';
class FilterButton extends Component {
render() {
return (
<button className={this.props.active ? 'active' : ''}
onClick={this.props.onClick}>
{this.props.displayName}
</button>
)
}
}
FilterButton.propTypes = {
active: PropTypes.bool.isRequired,
displayName: PropTypes.string.isRequired,
onClick: PropTypes.func.isRequired,
filterName: PropTypes.string.isRequired
};
export default FilterButton;
This approach works, but I'm thinking that it shouldn't be necessary to create two different containers. Which again lead me to my second attempt.
Second approach: single container containing multiple components.
Here, I made a larger container:
import React, { PropTypes, Component } from 'react';
import Config from '../../config';
import {connect} from 'react-redux';
import {toggleFilter} from '../actions';
import FilterButton from '../components/filterbutton'
import FilterInput from '../components/filterinput'
class FilterContainer extends Component {
render() {
const { active, currentInput, onChange, onClick } = this.props;
return (
<div className='filterController'>
<FilterInput displayName="Search" filterName={Config.filters.WITH_TEXT} currentInput={currentInput} onChange={onChange} />
<FilterButton displayName="Today" filterName={Config.filters.IS_TODAY} active={active} onClick={onClick}/>
<FilterButton displayName="On TV" filterName={Config.filters.ON_TV} active={active} onClick={onClick}/>
</div>
)
}
}
const mapStateToProps = (state, ownProps) => {
return {
active: !!state.program.filters[ownProps.filterName],
currentInput: state.program.filters[ownProps.filterName] ? state.program.filters[ownProps.filterName].input : ''
}
}
const mapDispatchToProps = (dispatch, ownProps) => {
return {
onClick: () => {
dispatch(toggleFilter(ownProps.filterName, ownProps.input))
},
onChange: newValue => {
dispatch(toggleFilter(ownProps.filterName, newValue.target.value))
}
}
}
export default connect(
mapStateToProps,
mapDispatchToProps
)(FilterContainer);
Here, all state interaction for the entire component is gathered in a single compoment. The components are the same here as in the first approach. This doesn't, however, really work: ownProps is empty in both mapStateToProps and mapDispathToProps. I may have misunderstood how the react-redux connection works.
So, given these things I have two questions: What's the best way to structure this component, in terms of containers and components? And secondly, why won't ownProps work similarily in the second approach as in the first?
Thank you for your time.
Not sure I have a specific answer regarding structure at the moment. As for "ownProps", that represents props that are specifically being passed in to a given component by its parent. Since you're connect()-ing FilterController, that means that "ownProps" would be coming from wherever you render that component, like: return <FilterController prop1="a" prop2={someVariable} />.
Based on how you have those map functions written, it looks like you really want to be connecting the FilterInput and FilterButton components rather than FilterController.

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