AngularFire how to remove multiple items from array? - angularjs

I am using Firebase and the AngularFire library. I am looking for a way to remove all items or a range of items from a $firebaseArray object. I don't see a straightforward way to do it in the documentation. Is there some way I'm not thinking of other than looping and removing items one by one? Please tell me that's not the only way!!

If there isn't a method in the $firebaseArray that does what you want, you can use the array's $ref() to perform Firebase SDK-style calls. The array content will be synchronized with the changes you make through the ref.
To delete all elements, call remove on the ref itself:
function removeAll(firebaseArray) {
return firebaseArray.$ref().remove();
}
To remove a range, perform an update in which the keys to be removed are set to null:
function removeRange(firebaseArray, start, end) {
var keys = {};
if (end === undefined) {
end = firebaseArray.length;
}
for (var i = start; i < end; ++i) {
keys[firebaseArray.$keyAt(i)] = null;
}
return firebaseArray.$ref().update(keys);
}
Both functions return promises.

I couldn't get the firebaseArray.$ref().remove() to work as the remove() function didn't exist on the object when ordered by child, but doing the following seemed to work though:
$firebaseUtils.doRemove(firebaseArray.$ref());

Related

Access returned computed array within method and manipulate

I have a computed array which is full of tags and updates depending on what selection i make in the select box. I would like to take this array and pass it to a method and then run a method to update what “results” have an active class. Although I get an array saying I can’t run forEach on this element.
Been through a few topics and understand computed properties dont work like that but surely there is a way around this.
https://jsfiddle.net/39jb3fzw/6/
Short Snippet
methods: {
updateOutput() {
var tags = this.tagArray;
tags.forEach(function(tag) {
console.log(tag);
})
}
},
computed: {
concatenated: function () {
var ret = this.selected.concat(this.selected2, this.selected3);
this.tagArray = ret;
//this.updateOutput();
return ret;
}
}
Full Output
https://jsfiddle.net/39jb3fzw/6/
Thanks again :slight_smile:
It looks like the issue is the line:
var ret = this.selected.concat(this.selected2, this.selected3);
That line of code is returning an empty string rather than an array. This is because this.selectedX is a string rather than an Array. This explains why tag.forEach is undefined. forEach doesn't exist on the String prototype.
You can create this an array instead be doing
var ret = [ this.selected, this.selected2, this.selected3 ]
From there you can set this.tagArray to ret
Hope this helps

Angular - Objects seem bound to eachother but arent

I have an edit page where the user can edit a file in the system, and then save it. When loading the file, I make two objects out of the result, one is bound to the view and the other I wish to keep (in its original state) until "save" is clicked, and then use it to compare vs the view-bound object, to see if any changes have been made.
So, when the page loads, this is being run
$http.get('/api/files/' + $stateParams.id)
.then(function (result) {
vm.fileTemp = result.data;
vm.fileTempCopy = result.data;
The fileTempCopy is not being touched or referenced by anything in the view or elsewhere in the controller, except in the save-method, where i check if they are alike or not. But somehow, both of them are updated when i make changes to the input fields (as if they were both used as ng-model for the inputs).
if(vm.fileTemp === vm.fileTempCopy)//in save-function
is always true, and their fields are exactly the same.
Why does this happen and how can I solve it?
Using the assignment operator, you are actually just referencing the original array. Arrays are reference types. That means, that they don't actually store values, they only store references to those values. What you where doing is copying a reference to a memory location, meaning that any changes to the memory at that location (including removing elements) will be reflected in both arrays.
So you will want to do this instead:
vm.fileTemp = angular.copy(result.data);
vm.fileTempCopy = angular.copy(result.data);
here is a very basic approach to checking an object's "value equality".
function isEquivalent(a, b) {
// Create arrays of property names
var aProps = Object.getOwnPropertyNames(a);
var bProps = Object.getOwnPropertyNames(b);
// If number of properties is different,
// objects are not equivalent
if (aProps.length != bProps.length) {
return false;
}
for (var i = 0; i < aProps.length; i++) {
var propName = aProps[i];
// If values of same property are not equal,
// objects are not equivalent
if (a[propName] !== b[propName]) {
return false;
}
}
// If we made it this far, objects
// are considered equivalent
return true;
}
//After your update Outputs: false
console.log(isEquivalent(vm.fileTemp, vm.fileTempCopy));

Removing records that exist in an array from ExtJS store

I have a store and an array. I want to remove records from the store if that record's value matches with values in the array. Following is is the code I am trying but it's not working. Can anyone suggest the correct way?
'store' is the actual store and 'filterItems' is the array of records I want to remove from 'store'.
store.each(function (record) {
for (var i = 0; i < filterItems.length; i++) {
if (record.get('ItemId') === _filterItems[i].get('ItemId')) {
itemIndex = store.data.indexOf(record);
store.removeAt(itemIndex );
}
}
});
Not sure about your code because i dont know all variables. Though its recommended to use the store.getRange() fn and iterate the array via for loop. Its better for performance.
var storeItems = store.getRange(),
i = 0;
for(; i<storeItems.length; i++){
if(Ext.Array.contains(filterItemIds, storeItems[i].get('id')))
store.remove(store.getById(storeItems[i].get('id')));
}
Here is an example which i tried right now and it works well.
https://fiddle.sencha.com/#fiddle/8r2
Try using the remove method of the store (docs)
store.remove(filterItems);
var indexes = [], i = 0;
dataviewStore.each(function(item, index){
if(item) {
if(item.data.columnId == columnId) {
indexes[i++] = index;
}
}
}, this);
dataviewStore.remove(indexes);
this is my example if your record is matches with the value then store the index of that item after storing indexes of all the items and remove them.
Otherwise you have to use for loop and remove them from end of the array.

Listener for every array element

i've created an array. Each element is a button object. Is there a possibility to hook mouseclick on every array at the same time? I mean something like this.
var Objects:Array = new Array
Objects[0] = new button(parameters)
Objects[1] = new button(parameters)
Objects[2] = new button(parameters)
Objects[n].addEventListener(MouseEvent.CLICK, Clicked(n));
function Clicked(n,...)
{
THECODE PROCEEEEDS for Objects[n]
}
I know that's not the clearest and most correct writing, but I'm asking if this is possible in similiar way? And how to do it? I know I can hook every mouseclick and then check if the clicked under the mouse is one of the array elements with for loop, but I'm asking about this way.
Yes. You are unable to directly pass an index into a listener, but you can retrieve that via calling indexOf() inside it.
for each (b in Objects) b.addEventListener(MouseEvent.CLICK, clicked);
// note, you just put function name here!
public function clicked(e:MouseEent):void {
var i:int=Object.indexOf(e.target);
if (i==-1) {
// panic behavior
return;
}
// now you can parse that index into something valuable
}

How would I remove a "row" in an array depending on the value of an element?

Here's what I'm currently doing/trying to do to accomplish my goal. But it is not removing the "row" the way I would like it too.
So, I'm making an object, then pushing it into an array. And the adding to the array part works fine and just as I expect.
var nearProfileInfoObj:Object = new Object();
nearProfileInfoObj.type = "userInfo";
nearProfileInfoObj.dowhat = "add";
nearProfileInfoObj.userid = netConnection.nearID;
nearProfileInfoObj.username = username_input_txt.text;
nearProfileInfoObj.sex = sex_input_txt.selectedItem.toString();
nearProfileInfoObj.age = age_input_txt.selectedItem;
nearProfileInfoObj.location = location_input_txt.text;
nearProfileInfoObj.headline = headline_input_txt.text;
theArray.push(nearProfileInfoObj);
So after that later on I need to be able to remove that object from the array, and it's not working the way I'm expecting. I want to take a variable whoLeft and capture their ID and then look in the array for that particular ID in the userid part of the object and if its there DELETE that whole "row".
I know you can do a filter with an array collection but that doesnt actually delete it. I need to delete it because I may be adding the same value again later on.
whoLeft = theiruserIDVariable;
theArray.filter(userLeaving);
public function userLeaving(element:*, index:int, arr:Array):Boolean
{
if (element.userid == whoLeft)
{
return false;
}
else
{
return true;
}
}
But this doesnt seem to be deleting the whole row like it implies. Does anyone know what i'm doing wrong?
Instead of modifying the original array, the new filtered array is returned by the filter method. So you need to assign the returned array to theArray.
Try this
theArray = theArray.filter(userLeaving);
EDIT This turned out to be slower than for loop:
An alternative to the hand coded loop could be something like this:
theArray.every(searchAndDestroy);
public function searchAndDestroy(element:*, index:int, arr:Array):Boolean
{
if (element.userid == whoLeft)
{
arr.splice(index,1);
return false;
}
return true;
}
As far as I know, every() terminates the first time the test function returns false. So the question is: for a big list, which is faster, the for loop or the loop that every() does with the overhead of the test function call.
EDIT #2 But this was faster than a for loop for a test I ran on an array of a million Points:
for each(var element:Object in theArray)
{
if (element.userid==whoLeft)
{
theArray.splice(theArray.indexOf(element),1);
break;
}
}
I think this is what you're looking for:
for(var i:uint = 0, len:uint = theArray.length; i<len; i++)
{
if(thisArray[i].id == whoLeft.id)
{
thisArray.splice(i, 1);
break;
}
}
However, do you really need it in an Array because you could always use a Dictionary which would mean accessing it by id which would be a lot simpler to remove.

Resources