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Removing local storage item with vanilla javascript

I'm working on a simple to-do list with vanilla js. I've managed to add the input to local storage, but have not been able to add the style changes(check strike through) to local storage, nor can I figure out how to remove one item at a time from storage. I have been able to clear all, just unable to remove each item separately. Below is my code, any advice is greatly appreciated.
//local storage setup
let saved = window.localStorage.getItem(input.value);
if (saved) {
list.innerHTML = saved;
}
//handle input submit
function handleSubmitForm(e) {
e.preventDefault();
let input = document.querySelector('input');
if (input.value != '') {
addTodo(input.value);
}
input.value = '';
window.localStorage.setItem(input.value, list.innerHTML);
}
//check off todo
function checkTodo(e) {
let item = e.target.parentNode;
if (item.style.textDecoration == 'line-through') {
item.style.textDecoration = 'none';
} else {
item.style.textDecoration = 'line-through';
}
window.localStorage.setItem(item);
}
//delete todo
function deleteTodo(e) {
let item = e.target.parentNode;
item.addEventListener('transitionend', function () {
item.remove();
});
item.classList.add('todo-list-item-fall');
window.localStorage.removeItem(item);
}

JavaScript Storage is a key-value pair. Just use a string-based key so you can remove, edit or read it easily.
// Set todo item
localStorage.setItem("todo1", "Stand-up meeting 9.15am");
// Read todo item
localStorage.getItem("todo1");
// Delete todo item
localStorage.removeItem("todo1");
It's better if you can save it as a JSON string because you can mark it as completed without delete, so you can find completed tasks too.
// Saving todo item as a JSON string
localStorage.setItem("todo1", JSON.stringify({ text: "Stand-up meeting 9.15am", completed: false }));
// Read it
const todo = JSON.parse(localStorage.getItem("todo1"));
// You can read the text
console.log(todo.text);
// Also you can mark it as completed and save it back
todo.completed = true;
localStorage.setItem("todo1", JSON.stringify(todo));

Storing object in localStorage is a tricky job.
Everything you store in the local or session storage is of type string
you can create an object like
item = {
value : ANY_VALUE
}
and save it in your localStorage using JSON.stringify
localStorage.setItem(`item`,JSON.stringify(item))
now when you want to update the item just update the object and again set using the ablove syntax
To access the saved item from the local storage use JSON.parse
yourItemObject = JSON.parse(localStorage.getItem())```
You can access values now using yourItemObject .value

It appears you're passing the whole HTML element (it passed as an object) inside the removeItem function. you need to pass the key instead.
try localStorage.removeItem(item.innerText);

If you are working with lists in localStorage. I would use something like this basic example:
function addTodo(key, item){
var list = getTodo(key);
list.push(item);
localStorage.setItem(key, JSON.stringify(list) );
}
function getTodo(key){
try{
var rawList = localStorage.getItem(key);
return JSON.parse(rawList) || [];
}
catch(e){
return [];
}
}
function removeTodo(key, id){
var list = getTodo(key);
var newlist = list.filter( function(item){
return item.id != id;
});
localStorage.setItem(key, JSON.stringify(newlist) )
}
function emptyTodo(key){
localStorage.removeItem(key);
}
addTodo('list', {
id: 1,
text: 'do shopping'
});
addTodo('list', {
id: 2,
text: 'study'
});
console.log( getTodo('list') );
removeTodo('list', 1);
console.log( getTodo('list') )
emptyTodo('list');

localStorage array.push

Could someone tell me how to push elements into an array in localStorage?
My code:
(localStorage.getItem('projects') === null) ? localStorage.setItem('projects', ['proj1', 'proj2', 'proj3']) : '';
var ItemGet = localStorage.getItem('projects');
function CreateObject() {
console.log(ItemGet);
var Serializable = JSON.parse(ItemGet);
Serializable.push('proj4');
console.log(ItemGet);
}
<button onclick="CreateObject()">Add Object</button>

General approach:
let old_data = JSON.parse(localStorage.getItem('projects'))
let new_data = old_data.push(some_new_data)
localStorage.setItem('projects',JSON.stringify(new_data))

I would do the following assuming that your data is not a multiDimensional array.
(localStorage.getItem('projects') === null) ? localStorage.setItem('projects',
JSON.stringify(['proj1', 'proj2', 'proj3'])) : '';
var ItemGet = localStorage.getItem('projects');
function CreateObject() {
var Serializable = JSON.parse(ItemGet);
Serializable.push('proj4');
localStorage.setItem('projects',JSON.stringify(Serializable));
}

The problem you are hitting is that data stored in localStorage has to be a string. You'll have to parse/stringify before settting/getting anything from local storage. If you didn't want to work with strings, you may find something like IndexedDB API
const stuff = [ 1, 2, 3 ];
// Stringify it before setting it
localStorage.setItem('stuff', JSON.stringify(stuff));
// Parse it after getting it
JSON.parse(localStorage.getItem('stuff'));
Here is an example of using IndexedDB API from the docs
const dbName = "the_name";
var request = indexedDB.open(dbName, 2);
request.onerror = function(event) {
// Handle errors.
};
request.onupgradeneeded = function(event) {
var db = event.target.result;
// Create an objectStore to hold information about our customers. We're
// going to use "ssn" as our key path because it's guaranteed to be
// unique - or at least that's what I was told during the kickoff meeting.
var objectStore = db.createObjectStore("customers", { keyPath: "ssn" });
// Create an index to search customers by name. We may have duplicates
// so we can't use a unique index.
objectStore.createIndex("name", "name", { unique: false });
// Create an index to search customers by email. We want to ensure that
// no two customers have the same email, so use a unique index.
objectStore.createIndex("email", "email", { unique: true });
// Use transaction oncomplete to make sure the objectStore creation is
// finished before adding data into it.
objectStore.transaction.oncomplete = function(event) {
// Store values in the newly created objectStore.
var customerObjectStore = db.transaction("customers", "readwrite").objectStore("customers");
customerData.forEach(function(customer) {
customerObjectStore.add(customer);
});
};
};
There are also other solutions out there like PouchDB depending on your needs

Say for example you have an array. This is how you can store it in the local storage.
let my_array = [1, 2, 3, 4];
localStorage.setItem('local_val', JSON.stringify(my_array))
Now to push any data into the local storage array you have to override by the new data like bellow
let oldArray = JSON.parse(localStorage.getItem('local_val'))
oldArray.push(1000)
localStorage.setItem('local_val', JSON.stringify(oldArray))

Get specifics ids in IndexedDB [duplicate]

I want to execute this query
select * from properties where propertyCode IN ("field1", "field2", "field3")
How can I achieve this in IndexedDB
I tried this thing
getData : function (indexName, params, objectStoreName) {
var defer = $q.defer(),
db, transaction, index, cursorRequest, request, objectStore, resultSet, dataList = [];
request = indexedDB.open('test');
request.onsuccess = function (event) {
db = request.result;
transaction = db.transaction(objectStoreName);
objectStore = transaction.objectStore(objectStoreName);
index = objectStore.index(indexName);
cursorRequest = index.openCursor(IDBKeyRange.only(params));
cursorRequest.onsuccess = function () {
resultSet = cursorRequest.result;
if(resultSet){
dataList.push(resultSet.value);
resultSet.continue();
}
else{
console.log(dataList);
defer.resolve(dataList);
}
};
cursorRequest.onerror = function (event) {
console.log('Error while opening cursor');
}
}
request.onerror = function (event) {
console.log('Not able to get access to DB in executeQuery');
}
return defer.promise;
But didn't worked. I tried google but couldn't find exact answer.

If you consider that IN is essentially equivalent to field1 == propertyCode OR field2 == propertyCode, then you could say that IN is just another way of using OR.
IndexedDB cannot do OR (unions) from a single request.
Generally, your only recourse is to do separate requests, then merge them in memory. Generally, this will not have great performance. If you are dealing with a lot of objects, you might want to consider giving up altogether on this approach and thinking of how to avoid such an approach.
Another approach is to iterate over all objects in memory, and then filter those that don't meet your conditions. Again, terrible performance.
Here is a gimmicky hack that might give you decent performance, but it requires some extra work and a tiny bit of storage overhead:
Store an extra field in your objects. For example, plan to use a property named hasPropertyCodeX.
Whenever any of the 3 properties are true (has the right code), set the field (as in, just make it a property of the object, its value is irrelevant).
When none of the 3 properties are true, delete the property from the object.
Whenever the object is modified, update the derived property (set or unset it as appropriate).
Create an index on this derived property in indexedDB.
Open a cursor over the index. Only objects with a property present will appear in the cursor results.
Example for 3rd approach
var request = indexedDB.open(...);
request.onupgradeneeded = upgrade;
function upgrade(event) {
var db = event.target.result;
var store = db.createObjectStore('store', ...);
// Create another index for the special property
var index = store.createIndex('hasPropCodeX', 'hasPropCodeX');
}
function putThing(db, thing) {
// Before storing the thing, secretly update the hasPropCodeX value
// which is derived from the thing's other properties
if(thing.field1 === 'propCode' || thing.field2 === 'propCode' ||
thing.field3 === 'propCode') {
thing.hasPropCodeX = 1;
} else {
delete thing.hasPropCodeX;
}
var tx = db.transaction('store', 'readwrite');
var store = tx.objectStore('store');
store.put(thing);
}
function getThingsWherePropCodeXInAnyof3Fields(db, callback) {
var things = [];
var tx = db.transaction('store');
var store = tx.objectStore('store');
var index = store.index('hasPropCodeX');
var request = index.openCursor();
request.onsuccess = function(event) {
var cursor = event.target.result;
if(cursor) {
var thing = cursor.value;
things.push(thing);
cursor.continue();
} else {
callback(things);
}
};
request.onerror = function(event) {
console.error(event.target.error);
callback(things);
};
}
// Now that you have an api, here is some example calling code
// Not bothering to promisify it
function getData() {
var request = indexedDB.open(...);
request.onsuccess = function(event) {
var db = event.target.result;
getThingsWherePropCodeXInAnyof3Fields(db, function(things) {
console.log('Got %s things', things.length);
for(let thing of things) {
console.log('Thing', thing);
}
});
};
}

Firebase issue, I need to take out values from first two nodes

I try to achieve the following: When count is changed to "2" I need the function to push the JSON, named "updates", to the specific place in database, and take names from PlayerQueue node (0:"Mik", 1:"Bg" etc.) and put it into the database as "id". So the thing is that I need it to take first two nodes (0 and 1 in this case) and take names out of it (Mik and Bg) and put them in the database as id1 and id2 (in this database I have only one id value but I will add it later), the issue is that I can't figure out how to take out names from the first two nodes.
My database:
And here is my code
import * as functions from 'firebase-functions';
import * as admin from 'firebase-admin';
import { resolve } from 'url';
//Game/queue/{queueId}/PlayerCount
admin.initializeApp(functions.config().firebase);
exports.createGame = functions.database.ref('Game/queue/PlayerCount').onUpdate((change, context) => {
const ref1 = admin.database().ref('/Game/queue/PlayerQueue').limitToFirst(1);
var tmp:String = 'esh';
ref1.once("value")
.then(result => {
tmp = result.val();
console.log(tmp)
var updates = {};
updates['id'] = tmp
updates['visible'] = {
place: 'a1',
sign: 'rock'
};
const after = change.after.val();
if(after.count == 2){
return admin.database().ref('/Game/allGames').push(updates);
}
return null
}).catch(reason => {
console.log(reason)
});
return null;
});

Since you're looking for the first two child nodes in the queue, you should order by their ID and then limit to getting 2 children:
const query = admin.database().ref('/Game/queue/PlayerQueue').orderByKey().limitToFirst(2);
Then you can listen for the value:
query.once("value").then(snapshot => {
snapshot.forEach(child => {
console.log(child.key+": "+child.val());
});
});
The above purely solves the "getting the first two child nodes".
Update: to get the two children into separate variables, you can do something like this:
query.once("value").then(snapshot => {
var first, second;
snapshot.forEach(child => {
console.log(child.key+": "+child.val());
if (!first) {
first = child.val();
}
else if (!second) {
second = child.val();
}
});
if (first && second) {
// TODO: do something with first and second
}
});

Use Firestore unless you have a valid reason to use the Realtime Database.
See Cloud Firestore triggers documentation on how to take action .onUpdate to qty 2. See documentation example below
exports.updateUser = functions.firestore
.document('users/{userId}')
.onUpdate((change, context) => {
// Get an object representing the document
// e.g. {'name': 'Marie', 'age': 66}
const newValue = change.after.data();
// ...or the previous value before this update
const previousValue = change.before.data();
// access a particular field as you would any JS property
const name = newValue.name;
// perform desired operations ...
});

indexeddb , how to use a cursor to update an array of objects

Question: How do I store a large array full of objects, all of which have 5 properties and all except the id property must be updated. Further more, why won't the code below work and how can I format it to work with the main question?
Info I've viewed:
https://developer.mozilla.org/en-US/docs/Web/API/IDBObjectStore/openCursor
https://developer.mozilla.org/en-US/docs/Web/API/IndexedDB_API/Using_IndexedDB
https://developer.mozilla.org/en-US/docs/Web/API/IDBObjectStore/createIndex
Note: I am aware of the setInterval and its inefficiency, it is for testing purposes so I do not have to click many times to check for a result.
<html>
<body>
<script type="text/javascript">
let count =0;
let storeBuilt = false;
const dbName = "the_name";
let version=82;
let storeName= "store82";
let storeBuilding= false;
setInterval(build,1000/24);
function build(){
hello()
}
function hello(){
let customerData = [];
for(let i=0;i<=50000;i++){
customerData.push({name:"bob",minX:random(),minY:random(),maxX:random(),maxY:random(),id:random()})
}
let request = indexedDB.open(dbName, version);
request.onsuccess= function(event){
let db = event.target.result;
let transaction = db.transaction( storeName,"readwrite").objectStore(storeName);
if( storeBuilding=== false&& storeBuilt=== false){
storeBuilding= true;
let additem = addData(customerData, transaction);
additem.onsuccess= function(e){storeBuilt=true}
} else if (storeBuilt=== true){
let updateitem= updateData(customerData, transaction);
}
};
request.onupgradeneeded = function(event) {
let db = event.target.result;
// Create an objectStore to hold information about our customers. We're
// going to use "ssn" as our key path because it's guaranteed to be
// unique - or at least that's what I was told during the kickoff meeting.
let objectStore = db.createObjectStore(storeName, {keyPath:"names",autoIncrement:true});
objectStore.createIndex("name","name",{unique:true});
// Use transaction oncomplete to make sure the objectStore creation is
// finished before adding data into it.
objectStore.transaction.oncomplete = function(event) {
// Store values in the newly created objectStore.
let customerObjectStore = db.transaction(storeName, "readwrite").objectStore(storeName);
}
};}
function random (){
return (Math.floor((Math.random() * 10) + 1))
}
function addData(data,transaction){
return transaction.add(data)
}
function updateData(data,transaction){
let openCursor = transaction.index("name").openCursor();
openCursor.onsuccess= function(event){
let cursor = event.target.result;
if (cursor){
alert (cursor);
for(let I in data){
let item = data[I];
if(item.id === cursor.value.id){
let updateProperty = cursor.value;
updateProperty.minX = item.minX;
cursor.update(updateProperty);
cursor.continue()
}
}
}{alert("none")}
}
}
function deleteData(data,transaction){
}
</script>
</body>
</html>

Not sure if I understand the problem clearly, but generally you will want to load the objects from the object store, modify each object's properties, and then store the objects in the object store. There are several ways to do this. One way is to use cursor.update, but I don't think you need to do this at all. Just overwrite the objects.
function storeThings(db, things, callback) {
var txn = db.transaction('store82', 'readwrite');
txn.oncomplete = callback;
var store = txn.objectStore('store82');
for(var thing of things) {
store.put(thing);
}
}
function open(callback) {
var request = indexedDB.open();
request.onsuccess = _ => callback(request.result);
}
var things = [{id:1}, {id:2}, {id:3}];
open(db => storeThings(db, things, _ => console.log('done')));
I am using IDBObjectStore.prototype.put to store the objects. The put method will either create or overwrite an object in the store. It will create a new object in the store when no matching object is found based on the keypath. It will replace an existing object in the store when a matching object is found.
In your case, you are using ssn string as a keypath. So, in other words, it will create new people if ssn not found, or overwrite people if ssn found. You just need to make sure that the ssn property is defined within each person object you pass to put, or indexedDB will complain.