extrategy
aiutiamo aziende e startup a raggiungere i propri obiettivi di business utilizzando internet, la tecnologia e un approccio lean
User: hotel
Pass: ctc
@TheStrazz86
A JavaScript library for building user interfaces
class HelloMessage extends React.Component {
render() {
return <div>Hello {this.props.name}!</div>;
}
}
ReactDOM.render(<HelloMessage name="World" />, mountNode);
class HelloMessage extends React.Component {
render() {
return React.createElement(
"div",
null,
"Hello ",
this.props.name
);
}
}
ReactDOM.render(React.createElement(HelloMessage, { name: "World" }), mountNode);
class Timer extends React.Component {
constructor(props) {
super(props);
this.state = {secondsElapsed: 0};
}
tick() {
this.setState((prevState) => ({
secondsElapsed: prevState.secondsElapsed + 1
}));
}
componentDidMount() {
this.interval = setInterval(() => this.tick(), 1000);
}
componentWillUnmount() {
clearInterval(this.interval);
}
render() {
return (
<div>Seconds Elapsed: {this.state.secondsElapsed}</div>
);
}
}
ReactDOM.render(<Timer />, mountNode);
State management refers to the management of the state of one or more user interface controls such as text fields, OK buttons, radio buttons, etc. in a graphical user interface.
Wikipedia
Redux is a predictable state container for JavaScript apps
You Might Not Need Redux
The state of your whole application is stored in an object tree inside a single store.
The only way to mutate the state is to emit an action, an object describing what happened.
To specify how the state tree is transformed by actions, you write pure reducers.
var add = function(text) {
return {
actionType: "addTodo",
text: text
};
};
function addTodo(state,text){
var toReturn = Object.assign({},state,{
todos:[...state.todos]
});
toReturn.todos.push(text);
return toReturn;
};
import { createStore } from 'redux';
import Reducers from 'src/Reducers';
let store = createStore(Reducers);
(Async Actions)
onClick() {
this.props.dispatch(actions.requestData())
this.api.list().then(response => {
this.props.dispatch(actions.requestDataSuccess(response.data))
}).catch(error => {
this.props.dispatch(actions.requestDataError(error))
})
}
return store => dispatch => action {
dispatch(action)
switch (action.type) {
case 'REQUEST_DATA':
api.list().then(response => {
dispatch(actions.requestDataSuccess(response.data))
}).catch(error => {
this.props.dispatch(actions.requestDataError(error))
})
}
}
In computer programming, a thunk is a subroutine used to inject an additional calculation into another subroutine.
Wikipedia
function reqeustDataThunk() {
return function (dispatch) {
dispatch(requestData())
return api.list().then(
data => dispatch(requestDataSuccess(response.data)),
error => dispatch(requestDataError(error))
);
};
}
store.dispatch(reqeustDataThunk());
A Saga is an independent component that reacts to domain events in a cross-aggregate, eventually consistent manner.
redux-saga is a library that aims to make side effects in Redux applications easier and better.
The mental model is that a saga is like a separate thread in your application that's solely responsible for side effects.
function* fetch() {
try {
const data = yield call(api.list);
yield put(actions.requestDataSuccess(data));
} catch (e) {
yield put(actions.requestDataError(e));
}
}
function* mySaga() {
yield takeLatest("REQUEST_DATA", fetch);
}
export default mySaga;
function *foo() {
yield 1;
yield 2;
yield 3;
yield 4;
yield 5;
}
const it = foo();
console.log( it.next() ); // { value:1, done:false }
console.log( it.next() ); // { value:2, done:false }
console.log( it.next() ); // { value:3, done:false }
console.log( it.next() ); // { value:4, done:false }
console.log( it.next() ); // { value:5, done:false }
console.log( it.next() ); // { value:undefined, done:true }
MobX is a battle tested library that makes state management simple and scalable by transparently applying functional reactive programming.
const triangle = {
base:2,
height:3,
color:'red',
get area() {
return (this.base * this.height) / 2
}
};
const report = () => {
console.log(triangle.area);
};
report();
const triangle = triangleFactory({
base:2,
height:3,
color:'red'
});
const report = () => {
console.log(triangle.area);
};
triangle.addChangeListener(report);
triangle.setBase(4);
const triangle = observable({
base:2,
height:3,
color:'red',
get area() {
return (this.base * this.height) / 2
}
});
const report = () => {
console.log(triangle.area);
};
autorun(report);
//report()
triangle.base = 4;
//no report()
triangle.color = 'blue';
By extrategy