I am using hooks and context api.I have multiple actions that write them into seperate file.my problem this:in another file how can I access state?
I use this file for create my contexts:
createContext.js
import React, { useReducer } from "react";
export default (reducer, actions, defaultValue) => {
const Context = React.createContext();
const Provider = ({ children }) => {
const [state, dispatch] = useReducer(reducer, defaultValue);
const boundActions = {};
for (let key in actions) {
boundActions[key] = actions[key](dispatch);
}
return (
<Context.Provider value={{ state, ...boundActions }}>
{children}
</Context.Provider>
);
};
return { Context, Provider };
};
and when I want to create context I pass actions ,reducer and default values to createContext file and get Context and Provider from that.like this:
productContext.js
import createDataContext from "./createDataContext";
import {storeProducts, detailProduct} from "../data";
const productReducer = (state, action) => {
switch (action.type) {
case "GET_ITEM":
return {...state, productDetail: action.productDetail};
case "ADD_TOTALS":
return {
...state,
cartSubTotal: action.cartSubTotal,
cartTotal: action.cartTotal,
cartTax: action.cartTax
};
case "ADD_TO_CART":
return {
...state,
products: action.tempProducts,
cart: [...state.cart, action.product]
};
default:
return state;
}
};
const getItem = (id) => {
const product = **products**.find(item => item.id === id);
return product;
}
const handleDetail = dispatch => (id) => {
const productDetail = getItem(id);
dispatch({type: "GET_ITEM", productDetail})
};
const addToCart = dispatch => (id) => {
let tempProducts = [...storeProducts];
const index = tempProducts.indexOf(getItem(id));
const product = tempProducts[index];
product.inCart = true;
product.count = 1;
const price = product.price;
product.total = price;
dispatch({
type: "ADD_TO_CART",
tempProducts,
product
});
const data = addTotals();
dispatch({
type: "ADD_TOTALS",
cartSubTotal: data.cartSubTotal,
cartTotal: data.cartTotal,
cartTax: data.cartTax
});
};
const addTotals = () => {
let subTotal = 0;
**cart**.map(item =>{ (subTotal += item.total)});
const tempTax = subTotal * 0.1;
const tax = parseFloat(tempTax.toFixed(2));
const total = subTotal + tax;
return {cartSubTotal: subTotal, cartTax: tax, cartTotal: total};
};
export const {Provider, Context} = createDataContext(
productReducer,
{
handleDetail,
},
{
products: storeProducts,
productDetail: detailProduct,
cart: [],
modalOpen: false,
modalProduct: detailProduct,
cartSubTotal: 0,
cartTax: 0,
cartTotal: 0
);
I can not access cart and products that are bold.how can I use them?
It looks like you're doing a lot of work in the action creator function that would make more sense as part of the reducer. For example, instead of this:
const productReducer = (state, action) => {
switch (action.type) {
case 'GET_ITEM':
return { ...state, productDetail: action.productDetail };
default:
return state;
}
};
const getItem = (id) => {
// no access to state!
const product = products.find((item) => item.id === id);
return product;
};
const handleDetail = (dispatch) => (id) => {
const productDetail = getItem(id);
dispatch({ type: 'GET_ITEM', productDetail });
};
You can do this:
// action value
{ type: 'GET_ITEM', id: 1234 }
// reducer
const productReducer = (state, action) => {
switch (action.type) {
case 'GET_ITEM':
const productDetail = state.products.find(
(item) => item.id === action.id
);
return { ...state, productDetail };
default:
return state;
}
};
Inside the reducer is where you have access to both the action and the state. Try to design your actions so that they contain the smallest amount of information possible to achieve your intention.
Related
when I lose in a hangman I want to reload my data in the API so that a new password appears. Unfortunately I have no idea how to reload it without reloading the whole page, is it even possible to run the api again on a button click for example?
import { createSlice, createAsyncThunk } from '#reduxjs/toolkit';
import axios from 'axios';
const url = 'https://random-word-api.herokuapp.com/word?number=1';
const initialState = {
password: '1',
misstake: 0,
usedChart: [],
};
export const getPassword = createAsyncThunk(
'hangman/getPassword',
async (thunkAPI) => {
console.log(1)
try {
const resp = await axios(url)
return resp.data
} catch(error){
return thunkAPI.rejectWithValue('api not working');
}
}
);
const HangManSlice = createSlice({
name: 'hangman',
initialState,
reducers: {
increaseError: (state) => {
state.misstake += 1
},
usedCharts: (state, action) => {
state.usedChart.push(action.payload)
},
restart: (state) => {
state.misstake = 0
state.usedChart = []
getPassword()
}
},
extraReducers: (builder) => {
builder
.addCase(getPassword.fulfilled, (state, action) => {
state.password = action.payload;
})
}
})
export const { increaseError, usedCharts, restart } = HangManSlice.actions
export default HangManSlice.reducer
You should dispatch the getPassword() from the "restart" button handler instead of calling it your reducer.
const RestartButton = () => {
const dispatch = useDispatch();
const restartHandler = () => {
dispatch(getPassword());
dispatch(restart())
};
return (
<button onClick={restartHandler}>Restart</button>
);
}
Another option is to use the getPassword thunk to initialize a new game like so:
import { createSlice, createAsyncThunk } from '#reduxjs/toolkit';
import axios from 'axios';
const url = 'https://random-word-api.herokuapp.com/word?number=1';
const initialState = {
loading: false,
password: '1',
misstake: 0,
usedChart: [],
};
export const startGame = createAsyncThunk(
'hangman/getPassword',
async (thunkAPI) => {
console.log(1)
try {
const resp = await axios(url)
return resp.data
} catch(error){
return thunkAPI.rejectWithValue('api not working');
}
}
);
const HangManSlice = createSlice({
name: 'hangman',
initialState,
reducers: {
increaseError: (state) => {
state.misstake += 1
},
usedCharts: (state, action) => {
state.usedChart.push(action.payload)
},
},
extraReducers: (builder) => {
builder
.addCase(startGame.pending, (state, action) => {
state.loading = true;
})
.addCase(startGame.rejected, (state, action) => {
state.loading = false;
})
.addCase(startGame.fulfilled, (state, action) => {
state.loading = false;
// store new password
state.password = action.payload;
// reset state
state.misstake = 0
state.usedChart = []
})
}
})
export const { increaseError, usedCharts, restart } = HangManSlice.actions
export default HangManSlice.reducer
Now you can dispatch startGame(), and the state will be reset with a new password.
I have two functions, one where I am able to send an order that updates the users balance amongst some other things, and another which retrieves the users balance for the user to see. Before any orders happen I still need to retrieve the balance for the user to see, thus I have broken my getBalance func from MarketLongFunc.
Using redux-toolkit and redux-thunk I have an ordersSlice.js that looks like this:
export const MarketLongFunc = createAsyncThunk(
"/order/marketlong",
async (value, thunkAPI) => {
const token = thunkAPI.getState().auth.user.token;
const newObj = {
value: value,
token: token,
};
let url = `http://localhost:3001/api/orders/marketlong`;
const response = await axios.post(url, newObj);
//getBalance()
return;
}
);
export const getBalance = createAsyncThunk(
"/order/getBalance",
async (value, thunkAPI) => {
const token = thunkAPI.getState().auth.user.token;
const newObj = {
token: token,
};
let url = `http://localhost:3001/api/orders/getBalance`;
const response = await axios.post(url, newObj);
return response.data;
}
);
const initialState = {
value: null,
error: null,
balance: null,
status: "idle",
orderStatus: "idle",
};
export const ordersSlice = createSlice({
name: "orders",
initialState,
reducers: {
reset: (state) => initialState,
resetStatus: (state) => {
state.orderStatus = "idle";
},
},
extraReducers(builder) {
builder
.addCase(MarketLongFunc.pending, (state, action) => {
state.orderStatus = "loading";
})
.addCase(MarketLongFunc.fulfilled, (state, action) => {
state.orderStatus = "success";
// getBalance();
// state.balance = action.payload;
})
.addCase(MarketLongFunc.rejected, (state, action) => {
state.orderStatus = "failed";
state.error = action.error.message;
})
.addCase(getBalance.pending, (state, action) => {
state.status = "loading";
})
.addCase(getBalance.fulfilled, (state, action) => {
// state.status = "success";
state.balance = action.payload;
state.status = "success";
})
.addCase(getBalance.rejected, (state, action) => {
state.status = "failed";
state.error = action.error.message;
});
},
});
export const { reset } = ordersSlice.actions;
export default ordersSlice.reducer;
Now in my next component the useEffect will call if there is no balance yet and the user is logged in. The way in which I was trying to solve my issue was to use the state.orderStatus = "success" under MarketLongFunc.fulfilled, this way hypothetically I can dispatch getbalance under the useEffect if a MarketLong is placed and then change the status with reset like the following:
export const Orderform = () => {
const user = useSelector((state) => state.auth.user);
const balance = useSelector((state) => state.orders.balance);
const status = useSelector((state) => state.orders.orderStatus);
const dispatch = useDispatch();
useEffect(() => {
if (!balance && user) {
dispatch(getBalance());
}
if (status == "success") {
dispatch(getBalance());
dispatch(resetStatus());
}
}, [balance]);
if (user) {
return (
<div>
<h1>
cash balance: ${balance ? Math.round(balance.balance) : "error"}
</h1>
<MarketLong />
</div>
);
}
return (
<div>
Login
</div>
);
};
The above code does not work currently as when I console.log(status) on refresh is is idle and when I use marketLong it is loading but it never makes it to fulfilled so still the only way to update the balance that is displayed after an order is to refresh the page. I want to update the displayed balance without refreshing the page as refreshing the page will have to make two other API calls on top of the getBalance. I have left some comments in where I tried things like just putting the getBalance function inside the MarketLongFunc in the ordersSlice, I also tried returning it etc but that did nothing and I figured fixing this issue in the useEffect with the status' would be the best way to fix this but I am open to hearing other solutions besides creating redundant code where I just basically type out the getBalance func inside marketLongFunc.
Another way that almost works is just adding dispatch(getBalance()) after dispatch(MarketLongFunc(longItem)); in my MarketLong react component like the following:
const addNewLong = async (e) => {
e.preventDefault();
const longItem = {
userInput: req.ticker,
quotePrice: req.quotePrice,
quantity: Item.quantity,
};
dispatch(MarketLongFunc(longItem));
dispatch(getBalance());
};
The problem with this is the first order never gets updated but after that it updates incorrectly as the balance will be off by one buy order. I imagine this is due to getBalance gettting called before MarketLongFunc but without setting a manual setTimeout func which seems like a clunky solution, I am not sure how to fix that with redux, you would think something like : if (dispatch(MarketLongFunc(longItem))) {dispatch(getBalance())}, but maybe this way needs to be changed in the ordersSlice (which I had tried and was not able to get it to work).
There are many ways to solve this problem - I will describe an approximate solution:
export const MarketLongFunc = createAsyncThunk(
"/order/marketlong",
async (value, thunkAPI) => {
const token = thunkAPI.getState().auth.user.token;
const newObj = {
value: value,
token: token,
};
let url = `http://localhost:3001/api/orders/marketlong`;
const response = await axios.post(url, newObj);
//getBalance()
return;
}
);
export const getBalance = createAsyncThunk(
"/order/getBalance",
async (value, thunkAPI) => {
const token = thunkAPI.getState().auth.user.token;
const newObj = {
token: token,
};
let url = `http://localhost:3001/api/orders/getBalance`;
const response = await axios.post(url, newObj);
return response.data;
}
);
const initialState = {
value: null,
error: null,
balance: null,
status: "idle",
orderStatus: "idle",
balanceNeedsToBeUpdated: true // <--- HERE
};
export const ordersSlice = createSlice({
name: "orders",
initialState,
reducers: {
reset: (state) => initialState,
},
extraReducers(builder) {
builder
.addCase(MarketLongFunc.pending, (state, action) => {
state.orderStatus = "loading";
})
.addCase(MarketLongFunc.fulfilled, (state, action) => {
state.orderStatus = "idle";
state.balanceNeedsToBeUpdated = true; // < ----- HERE
// getBalance();
// state.balance = action.payload;
})
.addCase(MarketLongFunc.rejected, (state, action) => {
state.orderStatus = "failed";
state.error = action.error.message;
})
.addCase(getBalance.pending, (state, action) => {
state.status = "loading";
})
.addCase(getBalance.fulfilled, (state, action) => {
// state.status = "success";
state.balance = action.payload;
state.status = "idle";
state.balanceNeedsToBeUpdated = false; // <---- HERE
})
.addCase(getBalance.rejected, (state, action) => {
state.status = "failed";
state.error = action.error.message;
});
},
});
export const { reset } = ordersSlice.actions;
export default ordersSlice.reducer;
export const Orderform = () => {
const user = useSelector((state) => state.auth.user);
const balance = useSelector((state) => state.orders.balance);
const status = useSelector((state) => state.orders.status);
const orderStatus = useSelector((state) => state.orders.orderStatus);
const balanceNeedsToBeUpdated = useSelector((state) => state.orders.balanceNeedsToBeUpdated);
const dispatch = useDispatch();
useEffect(() => {
if (user && balanceNeedsToBeUpdated) { //< ----- HERE
dispatch(getBalance());
}
}, [user, balanceNeedsToBeUpdated]); // < ---- HERE
if (user) {
if (status == 'loading' || orderStatus == 'loading') {
return <div>loading</div>;
}
return (
<div>
<h1>
cash balance: ${balance ? Math.round(balance.balance) : "error"}
</h1>
<MarketLong />
</div>
);
}
return (
<div>
Login
</div>
);
};
//....
const addNewLong = async (e) => {
e.preventDefault();
const longItem = {
userInput: req.ticker,
quotePrice: req.quotePrice,
quantity: Item.quantity,
};
dispatch(MarketLongFunc(longItem)); // < --- HERE
};
How do I access the basket in other components like Navbar to show the contents of cart ?
And please correct me if there is any logical errors in the code.
Thanks in advance.
const cartReducer = (state, action) => {
switch (action.type) {
// other cases
case 'INITIALIZE_CART':
return action.payload;
default:
return state;
}
};
const initialState = {
basket: []
};
const CartContext = createContext();
const CartProvider = ({ children }) => {
const [state, dispatch] = useReducer(cartReducer, initialState);
useEffect(() => {
axios.get('userdetails', {
headers: { "Authorization": localStorage.getItem('token') }
}).then(res => {
console.log(res)
dispatch({
type: 'INITIALIZE_CART',
payload: {
...initialState,
basket: res.data.cart
}
})
})
}, []);
return (
<CartContext.Provider value={{ state, dispatch }}>
{children}
</CartContext.Provider>
);
};
export const useStateValue = () => useContext(CartContext)
export default CartProvider
import the CartState and use it for accessing state and passing action
import { CartState } from '../Cart/StateProvider'
const [{ basket }, dispatch] = CartState()
I'm totally new to the redux-toolkit and still learning it, I'm kind of blocked at this step as I don't know how to implement it with redux-toolkit.
I have a system of toasts build in my redux store and this was my action.
MY Action
const setAlert = (msg, alertType, timeout = 5000) => (dispatch) => {
const id = uuidv4();
dispatch({
type: SET_ALERT,
payload: { msg, alertType, id },
});
setTimeout(() => dispatch({ type: REMOVE_ALERT, payload: id }), timeout);
};
My Old reducer
export default function (state = initialState, action) {
const { type, payload } = action;
switch (type) {
case SET_ALERT:
return [...state, payload];
case REMOVE_ALERT:
return state.filter((alert) => alert.id !== payload);
default:
return state;
}
}
I was thinking about creating a react component to render when an alert array is longer than 0 with useEffect but I think it would be overkill.
I was thinking also about creating createAsyncThunk action but I need to return the value of the alert so I can't set setTimeout as the function would return.
Is there a way to get the dispatch function in the reducer so it would dispatch removeAlert after timeout?
const initialState: [] = [];
const alertSlice = createSlice({
name: 'alert',
initialState,
reducers: {
setAlert(state, action) {
const id = uuidv4();
[...state, action.payload];
toast[action.payload.alertType](msg);
setTimeout(() => dispatch(removeAlert(id)), timeout);
},
removeAlert(state, action) {
return state.filter((alert) => alert.id !== action.payload);
},
},
});
I resolved it with hand-written thunk
https://redux.js.org/usage/writing-logic-thunks#async-logic-and-side-effects
const initialState: [] = [];
const alertSlice = createSlice({
name: 'alert',
initialState,
reducers: {
sA(state, action) {
[...state, action.payload];
toast[action.payload.alertType](action.payload.msg);
},
rA(state, action) {
return state.filter((a) => a.id !== action.payload.id);
},
},
});
export const { sA, rA } = alertSlice.actions;
export function alert(msg, alertType, timeout = 5000) {
return async (dispatch, getState) => {
const id = uuidv4();
const obj = {
msg,
alertType,
timeout,
id,
};
dispatch(sA(obj));
setTimeout(() => dispatch(rA(id)), timeout);
};
}
export default alertSlice;
I have a situation where i can successfully dispatch my states with reducers and i can render it in my component
Here the relevant code
in my action/index.js
export const receivedLeaguesList = json => ({
type: RECEIVE_LEAGUES_LIST,
json: json
});
export function fetchLeaguesList() {
return function(dispatch) {
dispatch(requestLeaguesList());
return axios
.get("https://www.api-football.com/demo/v2/leagues/")
.then(res => {
let leagues = res.data.api.leagues;
dispatch(receivedLeaguesList(leagues));
})
.catch(e => {
console.log(e);
});
}
}
my reducers/index.js
import { REQUEST_LEAGUES_LIST, RECEIVE_LEAGUES_LIST } from "../actions";
const initialState = {
leaguesList: [],
isLeagueListLoading: false
};
const reducer = (state = initialState, action) => {
switch (action.type) {
case REQUEST_LEAGUES_LIST:
return { ...state, isLeagueListLoading: true };
case RECEIVE_LEAGUES_LIST:
return { ...state, leaguesList: action.json, isLeagueListLoading: false };
default:
return state;
}
};
in my component component/Leagues.js
let Leagues = ({ leaguesList, loading, getList }) => {
useEffect(() => {
getList();
}, [getList]);
const [itemsLeagues] = useState([leaguesList]);
console.log("league list", itemsLeagues);
const mapDispatchToProps = {
getList: fetchLeaguesList
};
I have reproduced the demo here => https://codesandbox.io/s/select-demo-71u7h?
I can render my leaguesList states in my component doing the map, but why when
const [itemsLeagues] = useState([leaguesList]);
console.log("league list", itemsLeagues);
returns an empty array ?
See the image
You're setting useState's init value wrong:
const [itemsLeagues] = useState(leaguesList);
instead of
const [itemsLeagues] = useState([leaguesList]);
The return value of useState isn't the value itself, but the array of value and mutator:
const [value, setValue] = useState([42, 43])
// here's value equals [42, 43]
So if you were trying to destructure the wrapping array you passed to useState(), you should use it like this (though you don't need it):
const [[itemsLeagues]] = useState([leaguesList]);