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How do I avoid infinite loop when using Redux state in useEffect dependency array?

I'm trying to figure out why my useEffect function ends up in an infinite loop.
I have two variables that are hooked into my Redux store:
const vehicles: AllVehiclesCollection = useSelector((state: ReduxState) => state.claims?.vehicles ?? {});
const properties: AllPropertiesCollection = useSelector((state: ReduxState) => state.claims?.properties ?? {});
and I have an action that is dispatched to the store that updates these only after a user clicks a button.
I have a useEffect that will trigger based on either of these variables changing.
useEffect(() => {
let fullVehicleList: DropdownData[] = getFormattedVehicleListForDisplay();
let fullPropertyList: DropdownData[] = getFormattedPropertyListForDisplay();
let fullList = fullVehicleList.concat(fullPropertyList);
if (fullList.length > 0) {
setVehiclesAndPropertiesList(fullList);
} else {
setVehiclesAndPropertiesList(null);
}
}, [vehicles, properties]);
Nowhere in this code are the vehicles or properties variables changed or any actions dispatched that would change the Redux state.
getFormattedVehicleListForDisplay function:
const getFormattedVehicleListForDisplay = () => {
let list: DropdownData[] = [];
if (Object.keys(vehicles).length > 0) {
let thisPolicysVehicles = [];
if (vehicles !== null) {
const key = `${selectedPolicy.symbol}${selectedPolicy.number}`;
thisPolicysVehicles = vehicles[key];
}
if (thisPolicysVehicles && thisPolicysVehicles.length > 0) {
thisPolicysVehicles.forEach((vehicle: VehicleInformation) => {
if (vehicle.vehicleMake !== OTHER_VEHICLE) {
list.push({
label: formatVehicleForDisplay(vehicle),
value: { ...vehicle, type: 'V' },
});
} else {
list.push({ label: vehicle.vehicleMake, value: {} });
}
});
}
}
return list;
};
getFormattedPropertyListForDisplay function:
const getFormattedPropertyListForDisplay = () => {
let list: DropdownDataOMIG[] = [];
if (Object.keys(properties).length > 0) {
let thisPolicysProperties = [];
if (properties !== null) {
const key = `${selectedPolicy.symbol}${selectedPolicy.number}`;
thisPolicysProperties = properties[key];
}
if (thisPolicysProperties && thisPolicysProperties.length > 0) {
thisPolicysProperties.forEach((property: LocationInformation) => {
if (property.locStreet1 !== OTHER_PROP) {
list.push({
label: formatPropertyForDisplay(property),
value: { ...property, type: 'P' },
});
} else {
list.push({ label: property.locStreet1, value: {} });
}
});
}
}
return list;
};
For reference, the data in vehicles and properties is a set of key-value pairs where the key is a unique identifier of a given account number and the value is an array of vehicle/property objects for that account.
Any idea why this goes into an infinite loop when using Redux state in the dependency array? Is there a different way to use Redux state in a dependency array? Thanks!

When using
const vehicles = useSelector((state: ReduxState) => state.claims?.vehicles ?? {});
Each time this is triggered, and you don't have vehicles in your store, you return a new object {}. and {} === {} // false
So ain your useEffect dependency array, it's each time a new Object, so useEffect is triggered.
So either remove your || {} in your selector (because null === null & undefined === undefined) or consider moving to useShallowSelector as explained in react-redux documentation

Cannot read property 'slice' of undefined on class Cart

I have a problem with some class for cart , which I must use in my work.
Here is code of this class:
class Cart {
constructor() {
this.key = "IT_SPA_CART";
if (!this.exists()) {
this.setItSpaCart([]);
}
}
get() {
const cookies = document.cookie.split(";");
return cookies.find(cookie => cookie.startsWith(this.key));
}
exists() {
return this.get() !== undefined;
}
getItSpaCart() {
const cookieValue = this.get().slice(12);
const parsedValue = JSON.parse(cookieValue);
return parsedValue;
}
setItSpaCart(value) {
const stringifiedValue = JSON.stringify(value);
document.cookie = `${this.key}=${stringifiedValue}`;
}
add(item) {
const cartValue = this.getItSpaCart();
this.setItSpaCart([...cartValue, item]);
}
remove(item) {
const cartValue = this.getItSpaCart();
const itemInCart = cartValue.findIndex(val => val.name === item.name);
if (itemInCart !== -1) {
cartValue.splice(itemInCart, 1);
this.setItSpaCart(cartValue);
}
}
}
When I try to use this class, e.g. with method add(), like this:
let cart = new Cart();
cart.add([{ num: 1, cost: 2 }, { num: 3, cost: 4 }, { num: 5, cost: 6 }]);
this error occur:
Cannot read property 'slice' of undefined at Cart.getItSpaCart
Why this is happend?
Thanks for every hint.

I had the same problem ;-) Maybe You already know how to fix it, but if not, perhaps solution is changing code in this line: const cookies = document.cookie.split(";");. I changed ("; ) into ("; ").

unable to select all checkboxes in tree using angular2-tree on init

Objective : i have a button named "feed data" so when ever i click it the data will be loaded i mean the tree with checkboxes here my requirement is when ever i click it along with data all the check boxes have to be checked on init i tried using
this.treeComp.treeModel.doForAll((node: TreeNode) => node.setIsSelected(true));
but it is not working below is my code
click(tree: TreeModel) {
this.arrayData = [];
let result: any = {};
let rs = [];
console.log(tree.selectedLeafNodeIds);
Object.keys(tree.selectedLeafNodeIds).forEach(x => {
let node: TreeNode = tree.getNodeById(x);
// console.log(node);
if (node.isSelected) {
if (node.parent.data.name) //if the node has parent
{
rs.push(node.parent.data.name + '.' + node.data.name);
if (!result[node.parent.data.name]) //If the parent is not in the object
result[node.parent.data.name] = {} //create
result[node.parent.data.name][node.data.name] = true;
}
else {
if (!result[node.data.name]) //If the node is not in the object
result[node.data.name] = {} //create
rs.push(node.data.name);
}
}
})
this.arrayData = rs;
tree.selectedLeafNodeIds = {};
}
selectAllNodes() {
this.treeComp.treeModel.doForAll((node: TreeNode) => node.setIsSelected(true));
// firstNode.setIsSelected(true);
}
onTreeLoad(){
console.log('tree');
}
feedData() {
const results = Object.keys(this.data.info).map(k => ({
name: k,
children: this.data.info[k].properties
? Object.keys(this.data.info[k].properties).map(kk => ({ name: kk }))
: []
}));
this.nodes = results;
}
feedAnother() {
const results = Object.keys(this.dataa.info).map(k => ({
name: k,
children: this.dataa.info[k].properties
? Object.keys(this.dataa.info[k].properties).map(kk => ({ name: kk }))
: []
}));
this.nodes = results;
}
onActivate(event) {
this.selectedDataList.push(event.node.data);
console.log(this.selectedDataList)
}
onDeactivate(event) {
const index = this.selectedDataList.indexOf(event.node.data);
this.selectedDataList.splice(index, 1);
console.log(this.selectedDataList)
}
below is my stackblitz https://stackblitz.com/edit/angular-hrbppy

Use updatedata and initialized event to update the tree view to check all checkboxes.
app.component.html
<tree-root #tree *ngIf ="nodes" [nodes]="nodes" [options]="options" [focused]="true"
(initialized)="onTreeLoad()"
(updateData)="updateData()"
(select)="onActivate($event)"
(deselect)="onDeactivate($event)">
</tree-root>
It'll initiate tree-root component only if nodes variable is available,
then in the initialized and updateData event call selectAllNodes method to select all checkboxes.
app.component.ts
updateData() {
this.selectAllNodes();
}
onTreeLoad(){
this.selectAllNodes();
}
Refer to this slackblitz for working example.

just, in your function feed data call to your function this.selectAllNodes() enclosed in a setTimeout. You can see your forked stackblitz
setTimeout(()=>{
this.selectAllNodes()
})
NOTE: I see in your code you try to control in diferents ways the items selected. I simplified using a recursive function.
In this.treeComp.treeModel.selectedLeafNodeIds we have the items that are changed, so
getAllChecked()
{
const itemsChecked=this.getData(
this.treeComp.treeModel.selectedLeafNodeIds,null)
console.log(itemsChecked);
}
getData(nodesChanged,nodes) {
nodes=nodes||this.treeComp.treeModel.nodes
let data: any[] = []
nodes.forEach((node: any) => {
//in nodesChanged we has object like {1200002:true,123132321:false...}
if (nodesChanged[node.id]) //can be not changed, and then it's null because
//it's not in object or can be changed to false
data.push({id:node.id,name:node.name})
//or data.push(node.name); //if only need the "name"
if (node.children)
data=[...data,...this.getData(nodesChanged,node.children)]
}
);
return data
}
Updated I updated the function getData to include the "parent" of the node, but looking the code of #Raghul selvam, his function like me more than mine.
getData(nodesChanged,nodes,prefix) {
nodes=nodes||this.treeComp.treeModel.nodes
let data: any[] = []
nodes.forEach((node: any) => {
if (nodesChanged[node.id])
data.push(prefix?prefix+"."+node.name:node.name)
if (node.children)
data=[...data,...this.getData(nodesChanged,node.children,prefix?prefix+"."+node.name:node.name)]
}
);
return data
}
And call it as
this.getData(this.treeComp.treeModel.selectedLeafNodeIds,null,"")

You could add this in your onTreeLoad function. You could add a boolean flag(treeLoaded) for tracking if the tree has loaded or not.
onTreeLoad(tree){
this.selectAllNodes();
this.treeLoaded = true;
}

Can't update value into model generated by Constructor

I am trying to understand the OOP with the following example below. Can you please explain what am I doing wrong and why?
var shoppingcartModel = function() {
var _Cart = function() {
return {
totalPrice: {},
products: []
};
}
return {
cart: _Cart,
addProducts: function(product) {
return _Cart().products.push(product);
}
};
};
var shoppingCart = shoppingcartModel()
console.log(shoppingCart.cart())
shoppingCart.addProducts('product1')
shoppingCart.addProducts('product2')
console.log(shoppingCart.cart())

_Cart is a function that returns an object, not an object itself. Whenever you call Cart_(), including in addProducts, you create a new object, so whatever you push to one of the old objects is disregarded because no reference to the old object remains.
Try something like this instead:
var shoppingcartModel = function() {
const cart = {
totalPrice: {},
products: []
};
return {
cart,
addProducts: function(product) {
return cart.products.push(product);
}
};
};
var shoppingCart = shoppingcartModel()
console.log(shoppingCart.cart)
shoppingCart.addProducts('product1')
shoppingCart.addProducts('product2')
console.log(shoppingCart.cart)

node creating instances via costructors

While experimenting with nodejs I encountered a problem of enabling isntances creation via Constructors. I create simple cart basket functionality.
I got file cart.js
var items = [];
function addItem (name, price) {
items.push({
name: name,
price: price
});
}
exports.total = function () {
return items.reduce(function (a,b) {
return a + b.price;
}, 0);
};
exports.addItem = addItem;
I run it with node
var cart = require('./cart')
But what if I need to create multiple instances of a Cart?
I tried to refactor my code, creating a Constructor, that holds items[] addItem() and total() functions, like this:
exports.Cart = function () {
var items = [];
function addItem (name, price) {
items.push({
name: name,
price: price
});
}
function total () {
return items.reduce(function (a,b) {
return a + b.price;
}, 0);
}
};
I run it like this:
var cart = require('./cart');
cart.addItem('Pepsi',199); // no problem with this
cart2 = new cart.Cart(); // it gives me undefined can't be a function
I understand, that I can use PROTOTYPE property to add functions and props to my Cart
So I create a second file cart2.js and place something like:
function Cart () {
this.items = [];
}
Cart.prototype.addItem = function (name, price) {
this.items.push({
name: name,
price: price
});
};
Cart.prototype.total = function () {
return this.items.reduce(function (a,b) {
return a + b.price;
}, 0);
};
module.exports = Cart;
And now it works.
But in order to explore all possiblities, I want to know how I can solve it the first way I tried. When I can use it as "instanceble" Class thing and as singleton thing, with only one instance, at the same time.
Can you please advice me how to solve it the way I wanted in the first place?
I'll appreciate if you provide some other ways to solve this task of creating instanceable Classes.

The first option might look like this:
exports.Cart = function () {
var items = [];
// ...other private stuff...
return {
addItem: function (name, price) {
items.push({
name: name,
price: price
});
},
total: function() {
return items.reduce(function (a,b) {
return a + b.price;
}, 0);
}
// ...other public stuff...
}
};
Usage:
var carts = require('carts');
firstCart = carts.Cart();
second = carts.Cart();