My Array holds previous values too every time i use. - javascript

var TransactionObject = {
arr1: [],
arr2: []
};
My Array holds previous values too every time i use my model class.
var data = update(TransactionObject.arr1);
JsonClient.send(data );
The first time the array holds some value, and the next time when i make the request... it adds the previous data too... the array is not getting cleared at all.

If you want to clear the data each time before adding new data, then somewhere your code just needs to clear the array. You could do it like this:
TransactionObject.arr1 = [];
var data = update(TransactionObject.arr1);
JsonClient.send(data );
Or, you could do it inside your update() function like this before putting data into the passed array:
var data = update(TransactionObject.arr1);
JsonClient.send(data );
function update(results) {
results = [];
// now put data into results
}

Related

How to iterate through an array stored in Local Storage JavaScript?

In this application I am getting this information from users in an HTML form: var orderName, trackingNumber, price the user is updating these dynamically. Then I'm storing them in an array, converting it to json format, and keeping the orderName variable (which the user gave earlier) as the local storage key,
var myArray = [];
myArray.push(orderName, trackingNumber,price);
var JsonOrder = JSON.stringify(myArray );
localStorage.setItem(orderName,JsonOrder );
Now I want to display all the orders and their information. One page with all the orders listed, and the orderName should be a HYPERLINK that takes user to a page with information on just that order.
Here is what I'm doing to loop through the array:
var savedOrders = JSON.parse(localStorage.getItem('orderName'));
var orderName;
var trackingNumber;
var price;
for (var key in savedOrders ) {
orderName = savedOrders[key][0];
trackingNumber = savedOrders[key][1];
price = savedOrders[key][2];
}
This isn't working?
simply do
let JsonOrder = JSON.stringify( [orderName, trackingNumber, price] );
localStorage.setItem('someName',JsonOrder );
//---
let orderName, trackingNumber, price;
[orderName, trackingNumber, price] = JSON.parse(localStorage.getItem('someName'));
I found an answer here:
// Get the existing data
var existing = localStorage.getItem('myFavoriteSandwich');
// If no existing data, create an array
// Otherwise, convert the localStorage string to an array
existing = existing ? existing.split(',') : [];
// Add new data to localStorage Array
existing.push('tuna');
// Save back to localStorage
localStorage.setItem('myFavoriteSandwich', existing.toString());
from https://gomakethings.com/how-to-update-localstorage-with-vanilla-javascript/
I think there is a better way then to use split since what if the user enters a [] or , as their input?But so far this works just not a good method.

index value cannot updated

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);
}

count the number of rows in 2d array

Description:
I am adding the data in my 2D array like the following
my_2d_array['user1'] = {'id':name,'socket':socket};
my_2d_array['user2'] = {'id':name,'socket':socket};
This 2D array keeps the record of all the connected users id and their respective sockets ...
I want to display the number of users connected .. So far to do that would be to count the number of rows in the array and display it
I have tried following:
my_2d_array[].length; // this gives nothing
my_2d_array.length; // this outputs 0 (as number)
What should I do to get the number of rows
UPDATE
I declared my array like this
var my_2d_array = [];
This could work for you
// initialize
var my_2d_array = {};
// add users
my_2d_array["user1"] = ...
my_2d_array["user2"] = ...
// get number of users
Object.keys(my_2d_array).length;
//=> 2
You should consider using users instead of my_2d_array though. It communicates better and the actual data type is an Object, not specifically an Array.
Use push method
my_2d_array.push({'id':name,'socket':socket});
my_2d_array.push({'id':name,'socket':socket});
And my_2d_array.length to get the count
It looks like you are trying to figure out how many keys are in your javascript object my_2d_array.
You should be able to use Object.keys()
Here is a JsFiddle.
var my_2d_array = {};
var name = "Hello";
var socket = "World";
my_2d_array['user1'] = {'id':name,'socket':socket};
var name = "Hello2";
var socket = "World2";
my_2d_array['user2'] = {'id':name,'socket':socket};
alert( Object.keys(my_2d_array).length );

I want to insert values dynamically to hash map

var markerList1={};
var markerList=[];
and adding iterator values from the one for loop
function addSomething() // this function will multiple times from a for loop
{
image ='../css/abc/'+image[iterator]+'.png';
var data = respData[iterator];
var box = getbox(data);
var markerOpts = {
position : coordinates[iterator],
map : map,
icon :image,
title :data[1],
id : data[11]
};
var vmarks = new google.maps.Marker(markerOpts);
markerList.push(vmarks);
markerList1[markerOpts.title].push(vmarks);
}
whenever we call the function i want append the array's values to same index
markerList1[data[11]].push(vmarks);
but i'm not getting above result, when i markerList1[data[11]) then i'm getting only the last value i.e thirdvmark
i want output like this= markerList1[data[11]] = {firstvmark, secondvmark, thirdvmark};
You cannot do push to an object markerList1, only to an array.
change this
markerList1[markerOpts.title].push(vmarks);`
To this
markerList1[markerOpts.title] = vmarks;
markerList1[data[11]] is never initialized before you push something inside.
You can initialize it only once with a simple test:
if (! (data[11] in markerList1) ) {
markerList1[data[11]] = [];
}
markerList1[data[11]].push(vmarks);
Or in a shorter and safer way:
markerList1[data[11]] = markerList1[data[11]] || [];
markerList1[data[11]].push(vmarks);
(And please put data[11] in a variable)
Try this-
var vmarks = new google.maps.Marker(markerOpts);
markerList.push(vmarks);//you already pushing vmarks to array
markerList1[markerOpts.title]=markerList;//assign array to your markerList1 map

Numerically ordered ID's of data objects in Firebase

I am pretty new to the 'game' and was wondering if it's possible to order newly added data (through a form and inputs) to the Firebase numerically so each new data entry gets the ID (number of the last added data +1).
To make it more clear, underneath you can find a screenshot of how data is currently being added right now. The datapoint 0-7 are existing (JSON imported data) and the ones with the randomly created ID belong to new entries. I would like to have the entries to comply to the numbering inside of my Firebase, because otherwise my D3 bar chart won't be visualised.
var firebaseData = new Firebase("https://assignment5.firebaseio.com");
function funct1(evt)
{
var gameName = $('#nameInput').val();
var medalCount = $('#medalsInput').val();
var bool = $('#boolInput').is(':checked');
firebaseData.push().set({games: gameName, medals: medalCount, summergames: bool});
evt.preventDefault();
}
var submit = document.getElementsByTagName('button')[0];
submit.onclick = funct1;
UPDATE:
function funct1(evt)
{
var gameName = $('#nameInput').val();
var medalCount = $('#medalsInput').val();
var bool = $('#boolInput').is(':checked');
for (var i = 0; i < 10; i++)
{
firebaseData.child('7' + i).set({games: gameName, medals: medalCount, summergames: bool}(i)); };
Problem:
There are two ways to generate ids for your document nodes.
Calling .push() on your reference will generate that unique id.
Calling .set() on your reference will allow you to use your own
id.
Right now you're using .push().set({}), so push will generate an new id and the set will simply set the data.
// These two methods are equivalent
listRef.push().set({user_id: 'wilma', text: 'Hello'});
listRef.push({user_id: 'wilma', text: 'Hello'});
Using .set() without .push() will allow you to control your own id.
Using .push():
When managing lists of data in Firebase, it's important to use unique generated IDs since the data is updating in real time. If integer ids are being used data can be easily overwritten.
Just because you have an unique id, doesn't mean you can't query through your data by your ids. You can loop through a parent reference and get all of the child references as well.
var listRef = new Firebase('https://YOUR-FIREBASE.firebaseio.com/items');
// constructor for item
function Item(id) {
this.id = id;
};
// add the items to firebase
for (var i = 0; i < 10; i++) {
listRef.push(new Item(i));
};
// This will generate the following structure
// - items
// - LGAJlkejagae
// - id: 0
// now we can loop through all of the items
listRef.once('value', function (snapshot) {
snapshot.forEach(function (childSnapshot) {
var name = childSnapshot.name();
var childData = childSnapshot.val();
console.log(name); // unique id
console.log(childData); // actual data
console.log(childData.id); // this is the id you're looking for
});
});
Within the childData variable you can access your data such as the id you want.
Using .set()
If you want to manage your own ids you can use set, but you need to change the child reference as you add items.
for (var i = 0; i < 10; i++) {
// Now this will create an item with the id number
// ex: https://YOUR-FIREBASE.firebaseio.com/items/1
listRef.child('/' + i).set(new Item(i));
};
// The above loop with create the following structure.
// - items
// - 0
// - id: 0
To get the data you can use the same method above to loop through all of the child items in the node.
So which one to use?
Use .push() when you don't want your data to be easily overwritten.
Use .set() when your id is really, really important to you and you don't care about your data being easily overwritten.
EDIT
The problem you're having is that you need to know the total amount of items in the list. This feature is not implemented in Firebase so you'll need to load the data and grab the number of items. I'd recommend doing this when the page loads and caching that count if you really desire to maintain that id structure. This will cause performance issues.
However, if you know what you need to index off of, or don't care to overwrite your index I wouldn't load the data from firebase.
In your case your code would look something like this:
// this variable will store all your data, try to not put it in global scope
var firebaseData = new Firebase('your-firebase-url/data');
var allData = null;
// if you don't need to load the data then just use this variable to increment
var allDataCount = 0;
// be wary since this is an async call, it may not be available for your
// function below. Look into using a deferred instead.
firebaseData.once('value', function(snapshot) {
allData = snapshot.val();
allDataCount = snapshot.numChildren(); // this is the index to increment off of
});
// assuming this is some click event that adds the data it should
function funct1(evt) {
var gameName = $('#nameInput').val();
var medalCount = $('#medalsInput').val();
var bool = $('#boolInput').is(':checked');
firebaseData.child('/' + allDataCount).set({
games: gameName,
medals: medalCount,
summergames: bool
});
allDataCount += 1; // increment since we still don't have the reference
};
For more information about managing lists in Firebase, there's a good article in the Firebase API Docs. https://www.firebase.com/docs/managing-lists.html

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