meteor collection hooks updating element on a position in array - javascript

i have this object:
card: { customFields [ { id, value }, {id , value } ... ] }
A customFields array is inside cards, which contans elements consisting of an id and a value.
Now i want to update a certain element inside of the array, which can be done by doing something like this:
modifier.$set.customFields.0.value = x
but i have the number of the index only in a variable, so i tried:
const index = getTargetIndex();
modifier.$set.customFields[index].value = x
but it didn't work...
What do i have to add to the modifier.$set to update an element in this array?
Alternate Solution: i have the id of the element in the array if the update can be done on value by using the id.

Found a solution:
modifier.$set[`customFields.${ index }.value`]

It looks like you'll need to do it using a second update:
update(selector, modifier, options, callback) {
let i = 1;
let val = 20;
// The field in the array you want to modify
let _modifier = {$set: {"customFields.$.value": val}};
// The selector for main element and the array element
let _selector = Object.assign(selector, {"customFields.id": i});
// Update the array
super.update(_selector, _modifier);
// Continue with the actual update
return super.update(selector, modifier, options, callback);
}
I'm assuming it's safe to call super.update() twice in the same hook.

Related

Javascript search if LocalStorage variable exists

I am programming a chat system. I always make a Localstorage variable when a new chat is opened. Created like this:
localStorage.setItem("chat_"+varemail, data);
Now i want to check how many of them I have so something like:
"chat_"+... count.
How can I do this?
You'd grab the array of keys of the localStorage object, and use Array.filter to grab only the items starting with "chat_":
var length = Object.keys(localStorage).filter(function(key) {
return /^chat_.+/.test(key);
}).length;
Here's a JSFiddle
Try something like this, loop through all items in localStorage and match against your pattern
function getChatCount(){
var chatCount = 0;
for(item in localStorage){
if(item.indexOf('chat_') > -1) chatCount++;
}
return chatCount;
}
Local storage is based on key, value pairs. AFAIK, you wouldn't be able to retrieve all values with a certain prefix.
One potential solution would be to store an object that contains these. Based on your needs you could store the objects in an array or object and then retrieve the entire set and find the count.
For example:
var chats = { count: 0 };
chats["chat_"+varemail] = data;
chats.count += 1;
localStorage.setItem('chats', data);
Then if you want a count, you would retrieve the object:
var chats = localStorage.getItem('chats');
//chats.count would give you the count.
Although, this would mean you have to manually maintain the count variable when adding or removing data. If you don't need the indexing ability, you could add the chats to an array and store that.
EDIT: It is possible to find properties with a certain prefix, as seen in an answer to this question.
I would offer to convert to localStorage.setItem("chat", JSON.stringify(stack)), where stack is an array of chat objects. This way, you have access to an array of chats which you can count, search within, etc.
Something like:
var chatStore =
{
Count: function () {
var stack = JSON.parse(localStorage.getItem("chats"));
if (!stack)
return 0;
return stack.length;
},
Peek: function () {
var stack = JSON.parse(localStorage.getItem("chats"));
if (!stack)
stack = [];
if (stack.length > 0)
return stack.pop();
},
Push: function (token) {
var stack = JSON.parse(localStorage.getItem("chats"));
if (!stack)
stack = [];
stack.push(token);
localStorage.setItem("chats", JSON.stringify(stack));
},
// more methods to you might wish to implement: search, insert, etc.
}
// usage:
chatStore.Push(chatObject); // sets the last chat
chatStore.Peek(); // gets the last chat

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

access javascript array element by JSON object key

I have an array that looks like this
var Zips = [{Zip: 92880, Count:1}, {Zip:91710, Count:3}, {Zip:92672, Count:0}]
I would like to be able to access the Count property of a particular object via the Zip property so that I can increment the count when I get another zip that matches. I was hoping something like this but it's not quite right (This would be in a loop)
Zips[rows[i].Zipcode].Count
I know that's not right and am hoping that there is a solution without looping through the result set every time?
Thanks
I know that's not right and am hoping that there is a solution without
looping through the result set every time?
No, you're gonna have to loop and find the appropriate value which meets your criteria. Alternatively you could use the filter method:
var filteredZips = Zips.filter(function(element) {
return element.Zip == 92880;
});
if (filteredZips.length > 0) {
// we have found a corresponding element
var count = filteredZips[0].count;
}
If you had designed your object in a different manner:
var zips = {"92880": 1, "91710": 3, "92672": 0 };
then you could have directly accessed the Count:
var count = zips["92880"];
In the current form, you can not access an element by its ZIP-code without a loop.
You could transform your array to an object of this form:
var Zips = { 92880: 1, 91710: 3 }; // etc.
Then you can access it by
Zips[rows[i].Zipcode]
To transform from array to object you could use this
var ZipsObj = {};
for( var i=Zips.length; i--; ) {
ZipsObj[ Zips[i].Zip ] = Zips[i].Count;
}
Couple of mistakes in your code.
Your array is collection of objects
You can access objects with their property name and not property value i.e Zips[0]['Zip'] is correct, or by object notation Zips[0].Zip.
If you want to find the value you have to loop
If you want to keep the format of the array Zips and its elements
var Zips = [{Zip: 92880, Count:1}, {Zip:91710, Count:3}, {Zip:92672, Count:0}];
var MappedZips = {}; // first of all build hash by Zip
for (var i = 0; i < Zips.length; i++) {
MappedZips[Zips[i].Zip] = Zips[i];
}
MappedZips is {"92880": {Zip: 92880, Count:1}, "91710": {Zip:91710, Count:3}, "92672": {Zip:92672, Count:0}}
// then you can get Count by O(1)
alert(MappedZips[92880].Count);
// or can change data by O(1)
MappedZips[92880].Count++;
alert(MappedZips[92880].Count);
jsFiddle example
function getZip(zips, zipNumber) {
var answer = null;
zips.forEach(function(zip){
if (zip.Zip === zipNumber) answer = zip;
});
return answer;
}
This function returns the zip object with the Zip property equal to zipNumber, or null if none exists.
did you try this?
Zips[i].Zip.Count

jQuery getting value from dynamic array

I have an array with divs ids (in my case its all divs ID values od parent div (#area) ):
jQuery.fn.getIdArray = function () {
var ret = [];
$('[id]', this).each(function () {
ret.push(this.id);
});
return ret;
};
var array = $("#area").getIdArray();
I need to get an array field value, something like this:
var lef = $("#array".[0]).css("left");
Taking a wild swing at it (see my comment on the question):
var array = $("#area").getIdArray();
var lef=$("#" + array[0]).css("left");
That assumes that getIdArray returns an array of strings, where each string is an id value for a DOM element, and that you want to get the left value for the first of those elements.
So for instance, if the array comes back as:
["foo", "bar", "charlie"]
then the selector created by "#" + array[0] is #foo, so you end up getting the left value for the foo element.
If you have an actual JS array within your variable array just use bracket notation to access each individual ID.
// I have the # before-hand since I'm assuming you have just the ID name
var lef = $('#' + array[0]) // this will access the 1st one in the array
I think you are looking for this :
var divYouWantToChange = $("#"+array[0]);
I try to formulate this as an answer because getIdArray is not a jquery function and we don't know what it does. If you'd like to apply a custom filter to the $("#area") collection you can do so using filter. This will return a jquery object where you can get the .css("left") from.
If you'd like to save both the id's and the left property you can do so with the following code:
var objects=[];
$("#area").filter(function(){
$this=$(this);//cache the object
objects.push({id:$this.attr("id"),
left:$this.css("left")
};
});
console.log(objects);

Javascript indexOf method not working with integers in Object

I have made a fiddle:
http://jsfiddle.net/csS24/
I'm trying to get the code to a point, that it never ever shows the same two items at once or when one item is clicked, it never pulls back that same one from the array, just seem to be struggling a little with the logic and the indexOf method is behaving oddly.
var justAdded = [];
justAdded['first'] = 0;
justAdded['second'] = 1;
newHtml = returnRandom().split('|');
justAdded[e.id] = parseInt(newHtml[0], 10);
if(justAdded.indexOf(parseInt(newHtml[0], 10)) == -1){
e.style.opacity = 0;
e.innerHTML = newHtml[1];
e.style.opacity = 1;
e.setAttribute('data-id', newHtml[0]);
} else {
uniq(clickedEl);
}
var returnRandom = function(){
return options[Math.floor(Math.random() * options.length)]
};
e.id will be equal to 'first' or 'second'. returnRandom() will grab a random value from the options array:
var options = [
'0|Flash',
'1|Internet Explorer',
'2|Java',
'3|!important'
];
You seem to be adding non-numeric properties to an Array.
The indexOf() method is intended to work on and return numeric properties.
Furthermore...
the processAnswer handler passes the ID of the element to addHtml... like "first", "second"
addHtml uses that ID string to grab the very same element stored in a variable with the same name, and then passes that element to uniq
uniq adds a property to the justAdded Array, with the key being the ID of the element.
You keep switching between passing elements and their IDs, and using the one to get the other in every next function. All that is to say that your code seems terribly disorganized, and I think you just need to start from scratch and rethink your code.
Also, what the heck is with this?...
var options = [
'0|Flash',
'1|Internet Explorer',
'2|Java',
'3|!important'
];
Why are you hardcoding indices into strings in the Array? Arrays are ordered lists. They already have the indices taken care of.
var options = [
'Flash', // 0
'Internet Explorer', // 1
'Java', // 2
'!important' // 3
];

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