I am trying to create a cart with React js and Redux and I have one problem.
Tried many ways but I keep failing that when I add multiple items (food/drink) to the list then everything seems to be working, but then when I want for example add additional drink to the existing choice my list gets overwritten. Here is the code I have it now:
const addItemToCart = item => {
if (cartItems.length) {
cartItems.forEach(itemToCheck => {
if (item.name === itemToCheck.name) {
addCountToItem({ ...itemToCheck, count: itemToCheck.count + 1 });
} else if (item.name !== itemToCheck.name) {
addToCart({ ...item, count: 1 });
}
});
} else if (cartItems.length === 0) {
addToCart({ ...item, count: 1 });
}
};
Idea is that I can have multiple items on the list and unlimited number of same items within the list. So basically, I should be able to have 5 pizzas of the same type, 3 beers of different type etc.
I guess like any other cart. Thanks in advance.
update:
Here the code for addCountToItem. I deleted it but it was going something in this direction
state.cartItems[findIndex(...)] = data.cartItem
a basic way to solve your problem is
`let index=cartItem.findIndex(temp=>temp.name===item.name);
if(index>-1){
cartItem[index].count++;
}
else{
cartItem.append({...item, count: 1 })
}`
try not to mutate cartItem object
We need too see to all the related code to successfully answer.
Here I give sample example, updatedCartItems keeps the updated cart, you can do whatever you want. In general, this type of manipulation must be in the cart reducer, but you didn't post the the reducer code.
const addItemToCart = item => {
let updatedCartItems = [...cartItems];
updatedItemIndex = updatedCartItems.findIndex(
item => item.name === itemToCheck.name // better to check with some kind of id if exists
);
if (updatedItemIndex < 0) {
updatedCartItems.push({ ...item, count: 1 });
} else {
const updatedItem = {
...updatedCartItems[updatedItemIndex]
};
updatedItem.count++;
updatedCartItems[updatedItemIndex] = updatedItem;
}
//updatedCartItems => the new cart
};
for shopping card, we need to have cartItems property as array in our state, and every time we click on the addToCart button, we will push that item to that array and then we render that array in the cartDropdown component or the checkout page.
since you are able to add single item to the cart, it means that you have correct set up for redux. in order to add same item to the cart more than once, we just need to write a simple utility function.
here is the utility function:
export const addItemToCart = (cartItems, cartItemToAdd) => {
//find(condition) finds the first item in the array based on the condition.
const existingCartItem = cartItems.find(item => item.id === cartItemToAdd.id);
if (existingCartItem) {
//in order for change detection to trigger we have to rerender
//otherwise our quantity property will not be updated
//map will return a new array
//we need to return new versions of our state so that our component know to re render
//here we update the quantity property
return cartItems.map(item =>
item.id === cartItemToAdd.id
? { ...cartItemToAdd, quantity: item.quantity + 1 }
: item
);
}
//when you first time add a new item, sine exixtingCartItem will be falsy, it will pass the first if block and will come here
//quantity property gets attached the first time around since this if block wont run when it is a new item.
//in the beginning cartItems array is empty. every time you add a new item to this array, it will add "quantity:1" to this item object.
return [...cartItems, { ...cartItemToAdd, quantity: 1 }];
};
here is the action to add item to the cart
export const CartActionTypes = {
ADD_ITEM: "ADD_ITEM",
};
export const addItem = item => ({
type: CartActionTypes.ADD_ITEM,
payload: item
});
since you are able to add single item to the cart, it means that you have correct set up for redux. you need to dispatch this to the reducer in the component that you render addToCart button. here is the cart reducer where the case is CartActionTypes.ADD_ITEM.
import { addItemToCart } from "./cart.utils";
case CartActionTypes.ADD_ITEM:
return {
...state,
cartItems: addItemToCart(state.cartItems, action.payload)
};
Related
screeen record of the issue: https://streamable.com/ofn42v
it is working fine in local but once deployed to production(vercel), it is not working. i have tried sooo many different things like having a separate state in cart, useEffect with totalQuantity in dependency array and nothing seems to work. Ideally when the totalQuantity inside the context is updated, the components using it should rerender as mentioned in react doc which is happening from n to 2 except for 1. can someone please help :(
my code for the cart icon in nav bar:
function Cart(props) {
const { enableCart, totalQuantity } = useContext(AppContext);
return (
<>
{enableCart ? (
<Link href="/cart" passHref>
<a aria-label="Shopping cart" title="Shopping cart">
<Badge count={totalQuantity} offset={[0, 5]}>
<ShoppingCartIcon className="w-7 h-7" />
</Badge>
</a>
</Link>
) : null}
</>
);
}
Update quantity - code in appContext:
import { useCookies } from "react-cookie";
export const AppProvider = (props) => {
const [cartItems, updateCart] = useState([]);
const [totalQuantity, setTotalQuantity] = useState(0);
const [cookies, setCookie] = useCookies(["cart"]);
const cookieCart = cookies.cart;
useEffect(() => {
cartOperations();
}, []);
const calculateAmountQuantity = (items) => {
let totalCount = 0;
let totalPrice = 0;
items.forEach((item) => {
totalCount += item.quantity;
totalPrice += item.price * item.quantity;
setTotalAmount(totalPrice);
setTotalQuantity(totalCount);
});
};
const cartOperations = async (items) => {
if (items !== undefined) {
updateCart([...items]);
calculateAmountQuantity(items);
} else if (cookieCart !== undefined) {
updateCart([...cookieCart]);
calculateAmountQuantity(cookieCart);
} else {
updateCart([]);
setTotalAmount(0);
setTotalQuantity(0);
}
};
const addItem = (item) => {
let items = cartItems;
let existingItem;
if (items) existingItem = items.find((i) => i.id === item.id);
if (!existingItem) {
items = [
...(items || []),
Object.assign({}, item, {
quantity: 1,
}),
];
updateCart([...items]);
setTotalAmount(totalAmount + item.price * 1);
setTotalQuantity(totalQuantity + 1);
} else {
const index = items.findIndex((i) => i.id === item.id);
items[index] = Object.assign({}, item, {
quantity: existingItem.quantity + 1,
});
updateCart([...items]);
setTotalAmount(totalAmount + existingItem.price);
setTotalQuantity(totalQuantity + 1);
}
saveCartToCookie(items);
saveCartToStrapi(items);
};
i am storing the cart content in cookie.
code for AppContext is here in github, full nav bar code
Live url: https://sunfabb.com
Goto Products, add few items to cart, then try removing one by one from the cart page. (i have enabled react profiler in prod as well)
EDIT: This issue is completely specific to antd library. I was able to debug further based on the below 2 answers and there is nothing wrong with react context or re-render. i tried using a custom badge for cart and it is working perfectly fine. Yet to fix the antd issue though. I can go with custom one, but antd's badge is better with some animations.
As pointed out by #hackape, when setting the value of state to something that depends on the previous value of that state, you should pass a function to the setState instead of a value.
So instead of setTotalQuantity(totalQuantity + 1);, you should say setTotalQuantity(previousQuantity => previousQuantity + 1);.
This is the safe way of doing that, so for example if we are trying to do it twice simultaneously, they both get taken into account, instead of both using the same initial totalQuantity.
Other thing that I would think about changing is that you are setting those quantities and amounts in multiple places, and relying on the previous value. So if it goes out of sync once, it's out of sync also on the next action, and so on.
You could use the useEffect hook for this. Every time the cartItems change, calculate those values again, and do that based only on the new cartItems array, not on the old values.
Something like this for example:
useEffect(() => {
setTotalAmount(cartItems.reduce((total, currentItem) => total + (currentItem.price * currentItem.quantity), 0));
setTotalQuantity(cartItems.reduce((total, currentItem) => total + currentItem.quantity, 0));
}, [cartItems]);
Or if you prefer calling it like you do now, I would still replace the value with the reduce from my example, so it get's calculated based on the whole cart instead of previous value.
A shopping cart is usually something that contains less than 100 entries, so there is really no need to worry about the performance.
From looking at the renders and from seeing that after a refresh the cart shows as empty as should be, it's probably a lifecycle issue.
I'd suggest creating another useEffect hook that listens to totalQuantity or totalAmount (logically the bigger of the two though by the state values it looks either should be fine) and in the hook call change the cart icon based on the updated sum
EDIT:
misread your inter-component imports, because Cart (from components/index/nav.js) should listen for changes from the context.provider you would use a context.consumer on Cart with the totalQuantity value (not just with importing the variable from the context as that rides on the application rendering from other reasons)
see example in consumer docs and in this thread, and check this GitHub issues page for other's detailed journey while encountering this issue more directly
I have a state set as
const [filteredProducts, setFilteredProducts] = useState([]);
I want to be able to append to the end of that state. I am currently trying
products.forEach((product) => {
if (product.category === category) {
setFilteredProducts([...filteredProducts, product]);
}
});
It it looping through the products array correctly. I can even log the product after the setFilteredProducts and it logs the correct ones I want. I am calling this with an onClick.
Find all the products you want to add:
const productsToAdd = products.filter(product => product.category === category)
Then append them
setFilteredProducts((currentFilteredProducts) => ([...currentFilteredProducts, ...productsToAdd]));
The issue with your example is that filteredProducts may get stale after the first iteration. setFilteredProducts will not run synchronously, and filteredProducts keep the original value, until the re-render happen.
You would only append the last match to the existing filteredProducts array.
You can add all matches like so:
setFilteredProducts([...filteredProducts, ...products.filter((product) => product.category === category)]);
I'd recommend you do this in 2 steps:
Create an array of the new products you plan to add
let productsToAdd = [];
products.forEach((product) => {
if (product.category === category) {
productsToAdd.push(product);
}
});
Then combine the arrays and set state
setFilteredProducts([...filteredProducts, ...productsToAdd]);
I think you want what the ES6 built-in function does. You can rewrite your code to give you the the products that match the category like this:
const filteringTheProducts = products.filter(product => {
return product.category === category
})
setFilteredProducts(filteringTheProducts)
The result of the filtering will be the array of all the products that match that criteria.
Here is the documentation for .filter()
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/filter
The problem is, that setFilteredProducts doesn't immediately affect products. It's React's job to decide when to update the state. So when you loop over products, you'll probably ending up adding just the last item, because filteredProducts wasn't updated yet.
What you can do, is preparing an array of products to add:
const productsToAdd = products.filter(product => product.category === category);
And then append them:
setFilteredProducts([...products, ...productsToAdd]);
I have two functions , one of them adds an item in array and the other one delete from that array using React JS (hooks).[Both are handler of click event].
What I have works incorrectly.
``id`` comes from ``contact.length`` and I deleted it with``contacts.splice(id, 1)``.
I dont have any idea why it has this problem.
it doesnt delete what would be clicked but a random one.
function handleAddRecord(nameValue, phoneValue) {
setContacts([...contacts , {
id : contacts.length,
name : nameValue,
phone : phoneValue
}])
}
function handleDelete(id) {
console.log("manager", id);
const newContacts = contacts.splice([id],1);
setContacts([...newContacts]);
}
One of the issue on the implementation is id generation keeping it array length could lead to issue as you delete and add elements there could be scenarios where there is same id for multiple items.
One of most widely used generator is uuid https://www.npmjs.com/package/uuid
Usage
const uuid = require("uuid");
uuid.v4(); // ⇨ '9b1deb4d-3b7d-4bad-9bdd-2b0d7b3dcb6d'
Now use this in your implementation
Add Operation:
const handleAddRecord = (nameValue, phoneValue) => {
const newRecord = {
id: uuid.v4(), // This should be unique at all times
name: nameValue,
phone: phoneValue,
};
setContacts([...contacts, newRecord]);
};
Delete Operation:
Use filter rather than splice as for splice you'll need to find the index of the element with id. But with Filter it can be done is a single line
const handleDelete = (id) => {
setContacts(contacts.filter(item => item.id !== id));
};
Here we're assuming that id is the index of the element to be removed.
The splice function returns the removed elements, thus is not useful to take its result. Instead, make a copy of the array first, then remove the undesired element:
function handleDelete(id) {
console.log("manager", id);
const newContacts = [...contacts];
newContacts.splice(id,1);
setContacts(newContacts);
}
That's because splice alters the array itself.
More here: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/splice
Ok, id return index of current map?
Follow this example:
const assoc = [...contacts];
assoc.splice(id, 1);
setContacts(assoc);
You can delete the item by finding its index from array.
For Example:
function handleDelete(id) {
console.log("manager", id);
const index = contacts.findIndex((x) => x.id === id);
const newContacts = [
...contacts.splice(0, index),
...contacts.splice(index + 1),
];
setContacts(newContacts);
}
You need undestand, every time when i'll remove a item from a array of a index, that this index has use unique key... When React remove a item 6 (a example) this is remove of array first, and when react re-render function react can delete another component, because a array exist key 6, wehn you have more 6 item from array... Understand?
Follow a example:
import React, { useState } from 'react';
function User(data) { // data is a array
const [contacts, setContacts] = useState(data); // data return a list of contacts
/* contacts result a array object and has the following attributes
[{
name: 'Cael',
tel_number: '+55 11 9999-999',
e_mail: 'user#example.com',
! moment: "2021-06-15T05:09:42.475Z" // see this a date in ISO string
}]
*/
// about moment atribute:
// this atribute result when use `new Date().toISOString()`
// and this value is added in the moment that create a object in array list
// It's mean that every time result a unique key
const deleteFn = (val) => { // val result index of component and item array
const assoc = [...contacts];
assoc.splice(val, 1);
setContacts(assoc);
}
return (
<div>
{!!contacts.length &&
contacts.map((assoc, i) => { // variable i result in your id
const { moment, name, e_mail, tel_number } = assoc; // moment use a unique key
return (
<li key={moment}>
<span>{name}</span>
<span>{e_mail}</span>
<span>{tel_number}</span>
<button type="button" onClick={() => deleteFn(i)}>Delete</button>
</li>
);
})}
</div>
);
}
export default User;
I hope, this helpfull you!
Please know that I am new to ReactJS with Redux.
I have list of passengers, and each passenger has list of flights. I would like to update the flight property, checkedIn with the action property isCheckedIn. How can I achieve that with in reducer?
reducer.js
export default function passengerReducer(
state = initialState.passengers,
action
) {
switch (action.type) {
case types.LOAD_PASSENGERS_SUCCESS:
return action.passengers;
case types.UPDATE_PASSENGER_SUCCESS:
console.log("action ", action.passengerData.passengerId);
console.log("state ", state);
return state
.filter(x => x.id == action.passengerData.passengerId)
.map(f => {
f.flights[0].checkedIn = action.passengerData.isCheckedIn
});
default:
return state;
}
}
The state contains array of objects. Each object also contains flights. At the moment, I am only focusing the first flight with in flights array.
The action contains isCheckedIn property. I would like to update checkedInproperty of the flights with isCheckedIn property from action.
So this is the piece of code in question I presume:
case types.UPDATE_PASSENGER_SUCCESS:
console.log("action ", action.passengerData.passengerId);
console.log("state ", state);
return state
.filter(x => x.id == action.passengerData.passengerId)
.map(f => {
f.flights[0].checkedIn = action.passengerData.isCheckedIn
});
You're (a) filtering the array only for the element you want to change, and (b) mapping that but not returning anything from your map function
Just (a) alone is bad -- you're going to change your entire state to only include the filtered items? I don't think that's what you intended. But then (b) means you're returning an array full of undefined
What you want to do, instead, is create a new array, var newArray = state.slice(0);
Then, find the index of the item you want to change the checked_in property of,
var index = newArray.findIndex(x => x.id == action.passengerData.passengerId);
var newPassenger = Object.assign({}, newArray[index]);
newPassenger.flights[0].checkedIn = action.passengerData.isCheckedIn;
newArray[index] = newPassenger;
return newArray;
So you've found the item you wanted to change, changed it, put it back in the array (this is the immutable way to do things, I think), and then returned the FULL array
I am currently working on an online store that filters products based on certain criteria such as size, stock, gender, etc.
While I have been able to make it work to a certain extent. My program currently filters by size, gender, sorts by price etc. However, I cannot get it to filter by brand. For some reason once I click on the brand, I am able to filter the function once, however, once I click on another brand the filter for that particular brand does not run.
Here is the link to the code sandbox:
https://codesandbox.io/s/mystifying-roentgen-7mp0t
I am currently stuck with filtering by brand and I have tried to compared my filtered result to the state of the item clicked, by checking if the brand is included in the item and by using localeCompare().
Here is the link to the code sandbox:
https://codesandbox.io/s/mystifying-roentgen-7mp0t
createCheckboxes = () => available_sizes.map(this.createCheckbox);
handleFormSubmit = event => {
//4) this button updates the filters on the sizes, which I think I need to fix to update the brands, the price and the gender
event.preventDefault();
//5) right here I am storing the selected checkboxes which is what I was doing before by pushing the checkboxes
const selectedSizes = [...this.selectedCheckboxes];
const shallowCopy = [...this.state.filteredProducts];
let filteredProducts = shallowCopy.filter(product =>
selectedSizes.every(size =>
product.stock.some(s => s.stock > 0 && s.size === size)
)
);
let filteredGender = filteredProducts.filter(product => {
return product.gender.some((item, idx, arr) => {
return item[this.selectedGender] === false ? null : product;
});
});
//***this is the function that is not currently running***//
let filteredData = filteredGender.filter(product => {
//console.log(product.brand.includes(this.state.activeBrand))
//console.log(product.brand = this.state.brand)
return product.brand.includes(this.state.activeBrand)
});
let sortedPrice = filteredData.sort((a, b) => {
return this.state.sortBy === "min"
? a.price - b.price
: b.price - a.price;
});
this.setState({
filteredProducts: sortedPrice
});
};
I am expecting to be able to filter by brand wit this function, once an item is clicked.
Here is the link to the code sandbox:
https://codesandbox.io/s/mystifying-roentgen-7mp0t
There are 2 errors in your application:
1) the first one is reported by #user753642 in comment to your question, remove this line from index.js, because it sets your brand of all products to "":
console.log(product.brand = this.state.brand)
2) you are filtering filteredProducts and no the all products. While after first filtering on brand the filterdProducts does not have any item of other brands, it returns an empty collection after filtering on another brand. Change line in handleFormSubmit in index.js, from:
const shallowCopy = [...this.state.filteredProducts];
to:
const shallowCopy = [...this.state.products];