I have this code
function deleteElement() {
const myArray = map(listItems, getText);
var elementToDelete =document.getElementById('deleteElement').value;
const index = myArray.findIndex((item) => item.includes(elementToDelete));
if (index > -1) {
// delete and update local storage
console.log("found element and index ", index);
let moment = localStorage.getItem('pelis_guardades');
let deleted = moment.splice(index, 1);
localStorage.setItem('pelis_guardades', JSON.stringify(deleted))
console.log(deleted);
}
}
I have found the index of the element of the array that I want to delete, everything's good, but now I would like to "update" the local storage to delete the item from the index.
I can delete the specific value on the array that loads into the local Storage. Called myArray.
const myArray = map(listItems, getText);
myArray contains the "raw string data" that then gets put on the local Storage via,
localStorage.setItem('things',JSON.stringify(myArray));
How can I delete from the localStorage?
I've tried, the splice method on the local storage but doesn't work!!
Thanks!
try to parsing the moment variable to JSON
using
edit
function deleteElement() {
const myArray = map(listItems, getText);
var elementToDelete =document.getElementById('deleteElement').value;
const index = myArray.findIndex((item) => item.includes(elementToDelete));
if (index > -1) {
// delete and update local storage
console.log("found element and index ", index);
let moment = localStorage.getItem('pelis_guardades');
//try to add this code
let moment_parse = JSON.parse(moment);
let deleted = moment_parse.splice(index, 1);//edit
localStorage.setItem('pelis_guardades', JSON.stringify(deleted))
console.log(deleted);
}
before you splice the moment variable
The problem is that you've made a mistake using Array.splice.
This method mutates the given array.
You don't need the result of the splice operation. Instead you must pass the array as the new value to update the localstorage.
// 1. read value
const moment = JSON.parse(localStorage.getItem('pelis_guardades'))
// 2. mutate given array by removing one element from index.
moment.splice(index, 1);
// 3. write value
localStorage.setItem('pelis_guardades', JSON.stringify(moment))
Related
In the process of saving data to local storage.
I want to store objects in a key called 'DB'.
But I get an error saying "list.push is not a function." What's the problem?
let list = JSON.parse(localStorage.getItem('DB'));
const index = number++;
if (!list) {
const arr = [];
arr.push({
todo: text,
index: index
});
localStorage.setItem("DB", JSON.stringify(arr));
} else {
list.push({
todo: text,
index: index
});
console.log(list);
localStorage.setItem("DB", JSON.stringify(list));
}
If you already have something stored in the storage item DB that does not parse to an array, the code will fail. If I run it twice it does what I assume you want it to do, and I get a stringified array with two objects in my localStorage.
I suggest you try again, and if you have problems check what's in your localStorage.
As an aside, your code could be streamlined a little. For example:
let list = JSON.parse(localStorage.getItem('DB'));
// Maybe print out list here, to see what it is immediately after parsing
console.log('list:', list);
const index = number++;
if (!list) {
list = [];
});
list.push({
todo: text,
index: index
});
localStorage.setItem("DB", JSON.stringify(list));
When user click on button it will store some value in LocalStorage and if user click same button again it will store same value again in LocalStorage, How can i remove or avoid duplicates same values in LocalStorage ?!
Can anyone please help me :)
HTML:
<a onclick="AddToCart('ae90ac1a-64c4-49a7-b588-ae6b69a37d47');">Add to Cart</a>
<a onclick="AddToCart('3e58aa74-4585-4bee-b2e0-ed39a1d95442');">Add to Cart</a>
JavaScript:
function AddToCart(varer) {
var itemsLocalStorage = JSON.parse(localStorage.getItem("itemsline") || "[]");
itemsLocalStorage.push(varer);
localStorage.setItem("itemsline", JSON.stringify(itemsLocalStorage));
}
LocalStorage (Before user click) :
[]
LocalStorage (When user click ):
["ae90ac1a-64c4-49a7-b588-ae6b69a37d47"]
LocalStorage (When user click again):
["ae90ac1a-64c4-49a7-b588-ae6b69a37d47","ae90ac1a-64c4-49a7-b588-ae6b69a37d47"]
I tried with filter but for some reason it's not going to work:
itemsLocalStorage = itemsLocalStorage.filter(e => e === varer);
Grab the array from localStorage, push the value to the array if it's not found in that array already, and then update localStorage if we pushed.
var array = JSON.parse(window.localStorage.getItem("itemsline")) || [];//the "|| []" replaces possible null from localStorage with empty array
var value = "some value";
if(array.indexOf(value) == -1){
array.push(value);
window.localStorage.setItem("itemsline", JSON.stringify(array));
}
Here's a version of this same code that is more explanatory of how it works:
//All values stored in localStorage are strings.
//Grab our itemsline string from localStorage.
var stringFromLocalStorage = window.localStorage.getItem("itemsline");
//Then parse that string into an actual value.
var parsedValueFromString = JSON.parse(stringFromLocalStorage);
//If that value is null (meaning that we've never saved anything to that spot in localStorage before), use an empty array as our array. Otherwise, just stick with the value we've just parsed out.
var array = parsedValueFromString || [];
//Here's the value we want to add
var value = "some value";
//If our parsed/empty array doesn't already have this value in it...
if(array.indexOf(value) == -1){
//add the value to the array
array.push(value);
//turn the array WITH THE NEW VALUE IN IT into a string to prepare it to be stored in localStorage
var stringRepresentingArray = JSON.stringify(array);
//and store it in localStorage as "itemsline"
window.localStorage.setItem("itemsline", stringRepresentingArray);
}
Take temp array and then check for duplicate values.
var arr = ["ae90ac1a-64c4-49a7-b588-ae6b69a37d47","ae90ac1a-64c4-49a7-b588-ae6b69a37d47"]
function squash(arr){
var tmp = [];
for(var i = 0; i < arr.length; i++){
if(tmp.indexOf(arr[i]) == -1){
tmp.push(arr[i]);
}
}
return tmp;
}
console.log(squash(arr));
You could use filter
array.filter((item, index) => array.indexOf(item) === index)
const array = ["ae90ac1a-64c4-49a7-b588-ae6b69a37d47","ae90ac1a-64c4-49a7-b588-ae6b69a37d47"];
const filteredArray = array.filter((item, index) => array.indexOf(item) === index);
console.log(filteredArray)
You can use Set object of js it always add value only when it is unique
var array = JSON.parse(localStorage.getItem("items")) || [];
let set =new Set(array)
set.add(newValue)
const toArr=Array.from(set)
localStorage.setImem("items",JSON.stringify(toArr))
Here I am using array to store date in local-storage. first add data that is stored after add another one the index value not increased. The newly add data only shows.
function save() {
var task = [];
localStorage.getItem('task');
task.push(document.getElementById("txt1").value);
console.log(task);
localStorage.setItem('array', task);
}
I am working on a shopping cart application were users can click an Add to Cart button that will then add the specific item to local storage. When the user is adding a product to their shopping cart I need to be able to check to see if that specific item/value/product already exists in local storage. If it does, I need to increase only the count of that item/value/product by 1. If not, I need to add an entirely new item/value/product to local storage with a count of 1.
How can I find if an item already exists in local storage and compare it to the id of the current product that a user is attempting to add to their cart? My first few attempts failed miserably and have yet to find anything online that is helping with this issue. Is there a better way of going about this? Any assistance is appreciated. Even a good link to a good page would be extremely helpful.
Below is the code I have to attempt in checking for if the productid being added matches any of the productids in local storage. Basically if the productId that is being added matches the productId of an item in local storage simply add 1 to the quantity.
var retrieverObject = localStorage.getItem('Products');
var retrieveObject = JSON.parse(retrieverObject);
var data = {};
var productId = currentNode.name;
var product = currentNode;
data.productPrice = product.parentNode.previousSibling.previousSibling.id;
data.productId = productId;
var length = retrieveObject.length;
console.log(length);
for(var i = 0; i<length; i++){
if(retrieveObject[i].productId == data.productId){
var quantity = retrieveObject[i].quantity;
retrieveObject.push({"productPrice": data.productPrice, "productId": data.productId, "quantity": quantity++});
}else{
retrieveObject.push({"productPrice": data.productPrice, "productId": data.productId, "quantity": 1});
}
}
console.log(retrieveObject);
localStorage.setItem('Products', JSON.stringify(retrieveObject));
var retrievedObject = localStorage.getItem('Products');
var obj = JSON.parse(retrieverObject);
var len = obj.length;
console.log(len);
for(var i=0; i<len;i++){
console.log(obj[i]['productPrice']+", "+obj[i]['productId']);
}
}
}
There are a few issues. First, I am not entirely certain that the productId of the retrieved object is being compared to the one that is being added. Secondly, the for(var i = 0; i<length; i++){} definitely does not seem to be doing what was expected and is multiplying the number of items being added by 2. Thirdly, which may relate to the second issue, the retrieveObject.push() is not updating the quantity of the product but is adding an entire new entry to local storage. The given answers did not seem to be working for me before so this is what I have been working on. Any new answers or general help would be great.
PT 2. : So I am having an issue with the first entry into the local storage. Without noting that when there is nothing in local storage and you make a call to get the items in it, it returns null or undefined. So currently I have it set up like this:
if(localStorage.getItem("Products") === null || localStorage.getItem("Products") === undefined){
var data = {};
var productId = currentNode.name;
var product = currentNode;
data.productPrice = product.parentNode.previousSibling.previousSibling.id;
data.productId = productId;
var obj = [];
obj = obj[data.productId] = {
productPrice: data.productPrice,
count: 1
};
console.log(obj);
localStorage.setItem('Products', JSON.stringify(obj));
}
else{
var retrieverObject = localStorage.getItem('Products');
var retrieveObject = JSON.parse(retrieverObject);
var data = {};
var productId = currentNode.name;
var product = currentNode;
data.productPrice = product.parentNode.previousSibling.previousSibling.id;
data.productId = productId;
if(retrieveObject[data.productId]){
retrieveObject[data.productId].count++;
}else{
retrieveObject[data.productId] = {
productPrice: data.productPrice,
count: 1
};
}
console.log(retrieveObject);
localStorage.setItem('Products', JSON.stringify(retrieveObject));
}
This creates a first entry in local storage that looks like this : {"productPrice":"78.34","count":1}, and then when adding others looks like this: {"productPrice":"78.34","count":1,"rJUg4uiGl":{"productPrice":"78.34","count":3}} and works perfectly fine. The issue is getting the first entry to b formatted properly. When I change the code in the first if statement like so:
var obj = [];
obj[data.productId] = {
productPrice: data.productPrice,
count: 1
}
I get an empty [] in local storage but when I console.log the obj it is in the proper format. [rJUg4uiGl: Object]. I have been stuck on this and haven't been able to get it working. Again, any help would be really appreciated.
Once you have your data structure in obj, I would suggest using a dictionary with product IDs as keys.
To add the order or whatever, where you have:
obj.push({"productPrice": data.productPrice, "productId": data.productId});
Use:
if (obj[data.productId]) { // if the entry exists,
// increment the count
obj[data.productId].count++;
} else { // if it doesn't,
// add a new entry with count = 1
obj[data.productId] = {
productPrice: data.productPrice,
count: 1
};
}
Here is a complete function, including localStorage handling:
function addToCart(productID, productPrice) {
// get the current cart, or an empty object if null
var cart = JSON.parse(localStorage.getItem("Products")) || {};
// update the cart by adding an entry or incrementing an existing one
if (cart[productId]) {
cart[productId].count++;
} else {
cart[productId] = {
productPrice, // shorthand for `productPrice: productPrice,`
count: 1
};
}
// put the result back in localStorage
localStorage.setItem("Products", JSON.stringify(cart));
}
The solution above is preferable because you can check for a productId without looping through the whole list. If you really want to keep your current data structure of an array of objects, you could update it like this:
var length = retrieveObject.length;
console.log(length);
for (var i = 0; i < length; i++) {
if (retrieveObject[i].productId == data.productId) {
retrieveObject[i].quantity++; // update the entry in the array
} else {
retrieveObject.push({
productPrice: data.productPrice,
productId: data.productId,
quantity: 1
});
}
}
Note that you shouldn't push a new entry into the array; just update the existing one.
Just use localstorage.getItem; it returns null if the key doesn't already exist.
Assuming you are using localStorage node package you could do
if (localStorage.getItem('Products') !== null) {
localStorage.setItem('Products', JSON.stringify(obj));
}
Here is your reference:
https://www.npmjs.com/package/localStorage
Regards
Update:
Searching within your objet is a different story... so you want to check if the Product id is there then you can search for it using lodash
var _ = require('lodash');
// the rest of your code to get the data.productId set
if (localStorage.getItem('Products') !== null) {
var arrayOfProducts = localStorage.getItem('Products');
var existingProducts = _.filter(arrayOfProducts, function (product) { return product.productId === data.productId });
if (existingProducts.length > 0) {
// product found, do your logic
}
}
Here's lodash info https://www.npmjs.com/package/lodash
The other option is using a dictionary and having the productId as key and then using Object.keys to search for it... I've offered an approach that does not change your json structure.
I am trying to delete string out of array but the string is staying there. Any suggestions?
$scope.removeFavorites = function (word) {
debugger;
// retrieve it (Or create a blank array if there isn't any info saved yet),
var favorites = JSON.parse(localStorage.getItem('favoritesInfo')) || [];
for (var i = favorites.length - 1; i >= 0; i--) {
if (favorites[i] === word {
favorites.splice(i, 1);
console.log(favorites[i]);
}
}
//favorites.pop();
// localStorage.setItem('favoritesInfo', JSON.stringify(favorites));
console.log(localStorage.getItem('favoritesInfo'));
}
In the above code the splicing is being done to favorites array which gets the values from the localstorage
var favorites = JSON.parse(localStorage.getItem('favoritesInfo')) || [];
so the value is removed in favorites array but not in the localstorage.
localStorage.getItem('favoritesInfo') still contains the complete set of values.
You have two solutions.
Use the favorites array which is your filtered set of list where
ever needed.
Update the local storage with the favorites array to
keep both in sync.