Антон Спирин

const options = [
  {
    value: 'wifi',
    title: 'WiFi',
  },
  {
    value: 'isBT',
    title: 'BT',
  },
];

class Expample extends Component {
  state = {
    switch = '',
  };

  handleChange = e => {
    const { name, value } = e.target;
    
    this.setState({
      [name]: value,
    });
  };

  render() {
    
    return (
      <Wrapper>
        <SwitchGroup
          onChange={this.handleChange}
          name="switch"
          value={this.state.switch}
          options={options}
        />
      </Wrapper>
    );
  }
}

class SwitchGroup extends Component {
  ...
  handleClick(value) {
     const { name, onChange } = this.props;
     ...
     onChange({ 
       e: {
         target {
           name,
           value,
         },
       }
     });
  }

  render() {
    return(
      <Wrapper>
        {this.props.options.map((el, i) => (
          <Switch
           key={i}
           onClick={() => handleClick(el.value)}
           isActive={el.value === this.props.value}
           ...
          >
            {el.title}
          </Switch>
        ))}
      <Wrapper />
    );
  }
}

componentWillReceiveProps({ isOpen, article, loadArticleComments }) {
      loadArticleComments(article.id)
  }

componentWillReceiveProps({ isOpen, article, loadArticleComments }) {
      if (
           !article.commentsLoaded &&
           !article.commentsLoading &&
           !this.props.isOpen &&
           isOpen
         ) {
            loadArticleComments(article.id)
      }
  }

case "LOAD_ARTICLE_COMMENTS_SUCCESS": {
      return articleState
        .setIn(["entities", action.payload.articleId, "commentsLoading"], false)
        .setIn(["entities", action.payload.articleId, "commentsLoaded"], true);
    }

return (
    <div>
      <h5>{comment.user}</h5>
      {comment.text}
    </div>
  );

import { login } from './loginDucks';

class UserForm extends Component {
  ...
  handleSubmit = e => {
    this.props.login(this.state.form);
  }
  ...
  render() {
      const { isLoading, isError, shouldRedirect } = this.props;
      if (shouldRedirect) <Redirect to="/index" >;

    return (
      ...
    );
  }
}

const mapStateToProps = state => ({
  isLoading: state.login.isLoading,
  isError: state.login.isError,
  shouldRedirect: state.login.shouldRedirect,
});

const mapDispatchToProps = {
  login,
};

export default connect(mapStateToProps, mapDispatchToProps)(UserForm);

const LOGIN_REQUEST = 'LOGIN_REQUEST';
const LOGIN_SUCCESS = 'LOGIN_SUCCESS';
const LOGIN_ERROR = 'LOGIN_ERROR';

const loginSuccess = data => ({
  type: LOGIN_SUCCESS,
  payload: data,
});

const loginError = data => ({
  type: LOGIN_ERROR,
});

export const login = form => async dispatch => {
  try {
    const res = await axios.post('/api/user', form);

    if (!res.data) dispatch(loginError());
    
    dispatch(loginSuccess());
  } catch e {
    dspatch(loginError());
  }
}

const initialState = {
  isLoading: false,
  isError: false,
  shouldRedirect: false,
};

export default (state = initialState, action) => {
  const { type, payload } = action;

  switch(type) {
    case LOGIN_REQUEST:
      return { 
        ...state,
        isLoading: true,
        isError: false,
      };
    case LOGIN_SUCCESS:
      return { 
        ...state,
        isLoading: false,
        shouldRedirect: false,
      };
    case LOGIN_ERROR:
      return  { 
        ...state,
        isLoading: false,
        isError: true,
      };
    default:
      return state;
  }
};

import React from 'react';
import ReactDOM from 'react-dom';
import  { Provider } from 'react-redux';
import { createStore, combineReducers, compose, applyMiddleware } from 'redux';
import thunk from 'redux-thunk';
import { Route, Switch } from 'react-router';
import { BrowserRouter } from 'react-router-dom';
import Auth from './component/AuthForm';
import Helmet from './aplication';
import loginReducer from './loginDucks';

function user(state = {}, action){
    if(action.type === 'ADD_USER'){
        return [
            ...state,
            action.user
        ];
    }
    return state;
}

const rootReducer = combineReducers({
  login: loginReducer,
  user,
});

const composeEnhancers = window.__REDUX_DEVTOOLS_EXTENSION_COMPOSE__ || compose;

const store = createStore(rootReducer, composeEnhancers(
  applyMiddleware(thunk),
));

ReactDOM.render(
        <div>
            ...
        </div>,
    document.getElementById('content')

const Router = require('koa-router'),
    router = new Router();

router
    .get('*', async ctx => {
       await ctx.render('index');
    })

module.exports = router;

export const getReq = data => (
  async dispatch => {
    try {
      dispatch({
        type: types.GET_REQUEST,
      });

      let res = await api.getReq(data);
      
      dispatch({
        type: types.GET_SUCCESS,
        payload: res,
      });

      res = await api.getReq2(data); 

    } catch (error) {
      dispatch({
        type: types.GET_ERROR,
      });
    }
  }
);

export const getReq = data => (
  async dispatch => {
    try {
      dispatch({
        type: types.GET_REQUEST,
      });

      const res = await api.getReq(data);
      
      dispatch({
        type: types.GET_SUCCESS,
        payload: res,
      });

      dispatch(req2(res));
    } catch (error) {
      dispatch({
        type: types.GET_ERROR,
      });
    }
  }
);

const { date: TodayDate, transactions } = this.state;

const TodayDate = this.state.date;
const transactions = this.state.transactions;

class Example extends React.Component {
  handleClick = e => {
    alert(`
      target: ${e.target.tagName}
      currentTarget: ${e.currentTarget.tagName}
      `);
  };
  
  render() {
    return <button onClick={this.handleClick}><p>click me</p></button>;
  }
}

function withLog(WrappedComponent) {
  return class extends React.Component {
    displayName = WrappedComponent.displayName || WrappedComponent.name;
    
    componentDidMount() {
      console.log(`[${this.displayName}]: componentDidMount`);
    }

    ...

    render() {
      console.log(`[${this.displayName}]: render`);
      return <WrappedComponent {...this.props} />;
    }
  }
}

class MyComp extends React.Component {
  ...
}

const MyCompWithLog = withLog(MyComp);

export const addComponent = data => {
  return async function(dispatch) {     //  тут добавлен return и аргумент
    let comps = await fire.database().ref("components");
    comps.push({
      name: data.component,
      comp: data.component_name
    });

     //так же в любое время вы можете вызвать dispatch
     dispatch({ type: 'someAction', payload: 'someValue' });
  };
}

const foo = x => {
  return  y => {
    return x + y;
  }
};

const foo = x => y => x + y;

const a = x(5);
const b = a(6);

console.log(b);
// => 11

export const addComponent = data => async dispatch => {
  let comps = await fire.database().ref("components");
  // функция продолжит выполнение только когда вернется значение присвамваемое comps
  comps.push({
    name: data.component,
    comp: data.component_name
  });
};

<Wrapper>
  {array.map(el => (
    <MyComponent key={el.id} style={{ color: el.color }}>
      {el.title}
    </MyComponent>
  ))}
</Wrapper>

class Example extends React.Component {
  render() {
    return <span>{this.props.someValue}</span>;
  }
}

function Example (props) {
  return <span>props.someValue</span>;
}

#root
= javascript_pack_tag 'SearchUsers', {data: @users.to_json(only: [:id, :name, :email]) }

import React, {Component} from 'react';
import PropTypes from "prop-types";
import ReactDOM from 'react-dom';

let data = [];  // задаем значение по-умолчанию

try {
  data = JSON.parse(document.querySelector('script[data]').getAttribute('data'));  
} catch(e) {
  console.log(e);  // тут можно обработать ошибку парсинга данных
}

const User = ({ name, email }) => (
  <section id={name}> 
    <h1> {name} </h1>
    <h2> {email} </h2>
  </section>
);

const Users = ({ user }) => (
  <div className="users">
    {user.map(user => 
      <User key={user.id} {...user} />  // обратите внимание, заменено значение свойства key
    )}
  </div>
);
  
ReactDOM.render(
  <Users user={data} />,
  document.getElementById('root')
);

createCheckboxes = () => {
  const data = this.props.pets[0] || {};
  const newAnimals = Object.values(data).map(el => el.animal);
 
  this.setState(({ animals }) => ({
    animals: [ ...animals, ...newAnimals ],
  }));
};

let counterReducer = (state=initialState, action) => {
    let newstate = { ...state };

    switch(action.type){
        case "INC":
            newstate.counter+=action.payload
            return newstate
        case "DEC":
            newstate.counter+=action.payload
            return newstate
        default:
            return newstate
    }
}