I'm using tom-select for multiple select field with drag & drop plugin
Options provided to the select are alphabetically sorted, everything works fine when I choose some items, they are saved in db in the order I'v sorted them manually, as expected. Problem is that when I reload the page those selected items are shown in alphabetical order anyway. Is there any way to sort them custom way ?
Tom Select will order items (selected options) as instructed by your code.
new TomSelect('#your-select',{
items:['a','b']
});
vs
new TomSelect('#your-select',{
items:['b','a']
});
If you don't tell Tom Select how you want items ordered, it will use the order of the options in the select.
I'v resolved it by passing selected ids if I want to have it ordered by selection order, not options order, part of stimulus controller:
static values = { selectedIds: Array }
...
connect(){
if(this.selectedIdsValue && this.selectedIdsValue.length > 0) {
config.items = this.selectedIdsValue
}
}
In ExtJS panel I need to set value of all items (e.g. textfield, pathfield) to blank. I don't want to set value of each individual item to blank but of whole panel in one go.
I am able to get list of items
function getAllChildren (panel) {
/*Get children of passed panel or an empty array if it doesn't have thems.*/
var children = panel.items ? panel.items.items : [];
/*For each child get their children and concatenate to result.*/
CQ.Ext.each(children, function (child) {
children = children.concat(getAllChildren(child));
});
return children;
}
but how to set to blank for whole panel? Please suggest what need to be done in this case.
Actually, it's not possible to do it with one liner - all at the same time. What your method returns is purely an array of objects. In fact if such syntax existed, it would iterate over all fields anyway.
Though clearing all fields, having the method you've proposed is very trivial to do. Just iterate over them all and call reset method. Mind some (especially custom) widgets might not handle it.
var fields = getAllChildren(panel);
CQ.Ext.each(fields, function(field) {
if (child.reset) {
child.reset();
}
});
You've got similar loop in your getAllChildren code - you might reset field at the same place.
The method is defined in Field type which is usually a supertype of each dialog widget. You can read more here.
I'm trying to test out Firebase to allow users to post comments using push. I want to display the data I retrieve with the following;
fbl.child('sell').limit(20).on("value", function(fbdata) {
// handle data display here
}
The problem is the data is returned in order of oldest to newest - I want it in reversed order. Can Firebase do this?
Since this answer was written, Firebase has added a feature that allows ordering by any child or by value. So there are now four ways to order data: by key, by value, by priority, or by the value of any named child. See this blog post that introduces the new ordering capabilities.
The basic approaches remain the same though:
1. Add a child property with the inverted timestamp and then order on that.
2. Read the children in ascending order and then invert them on the client.
Firebase supports retrieving child nodes of a collection in two ways:
by name
by priority
What you're getting now is by name, which happens to be chronological. That's no coincidence btw: when you push an item into a collection, the name is generated to ensure the children are ordered in this way. To quote the Firebase documentation for push:
The unique name generated by push() is prefixed with a client-generated timestamp so that the resulting list will be chronologically-sorted.
The Firebase guide on ordered data has this to say on the topic:
How Data is Ordered
By default, children at a Firebase node are sorted lexicographically by name. Using push() can generate child names that naturally sort chronologically, but many applications require their data to be sorted in other ways. Firebase lets developers specify the ordering of items in a list by specifying a custom priority for each item.
The simplest way to get the behavior you want is to also specify an always-decreasing priority when you add the item:
var ref = new Firebase('https://your.firebaseio.com/sell');
var item = ref.push();
item.setWithPriority(yourObject, 0 - Date.now());
Update
You'll also have to retrieve the children differently:
fbl.child('sell').startAt().limitToLast(20).on('child_added', function(fbdata) {
console.log(fbdata.exportVal());
})
In my test using on('child_added' ensures that the last few children added are returned in reverse chronological order. Using on('value' on the other hand, returns them in the order of their name.
Be sure to read the section "Reading ordered data", which explains the usage of the child_* events to retrieve (ordered) children.
A bin to demonstrate this: http://jsbin.com/nonawe/3/watch?js,console
Since firebase 2.0.x you can use limitLast() to achieve that:
fbl.child('sell').orderByValue().limitLast(20).on("value", function(fbdataSnapshot) {
// fbdataSnapshot is returned in the ascending order
// you will still need to order these 20 items in
// in a descending order
}
Here's a link to the announcement: More querying capabilities in Firebase
To augment Frank's answer, it's also possible to grab the most recent records--even if you haven't bothered to order them using priorities--by simply using endAt().limit(x) like this demo:
var fb = new Firebase(URL);
// listen for all changes and update
fb.endAt().limit(100).on('value', update);
// print the output of our array
function update(snap) {
var list = [];
snap.forEach(function(ss) {
var data = ss.val();
data['.priority'] = ss.getPriority();
data['.name'] = ss.name();
list.unshift(data);
});
// print/process the results...
}
Note that this is quite performant even up to perhaps a thousand records (assuming the payloads are small). For more robust usages, Frank's answer is authoritative and much more scalable.
This brute force can also be optimized to work with bigger data or more records by doing things like monitoring child_added/child_removed/child_moved events in lieu of value, and using a debounce to apply DOM updates in bulk instead of individually.
DOM updates, naturally, are a stinker regardless of the approach, once you get into the hundreds of elements, so the debounce approach (or a React.js solution, which is essentially an uber debounce) is a great tool to have.
There is really no way but seems we have the recyclerview we can have this
query=mCommentsReference.orderByChild("date_added");
query.keepSynced(true);
// Initialize Views
mRecyclerView = (RecyclerView) view.findViewById(R.id.recyclerView);
mManager = new LinearLayoutManager(getContext());
// mManager.setReverseLayout(false);
mManager.setReverseLayout(true);
mManager.setStackFromEnd(true);
mRecyclerView.setHasFixedSize(true);
mRecyclerView.setLayoutManager(mManager);
I have a date variable (long) and wanted to keep the newest items on top of the list. So what I did was:
Add a new long field 'dateInverse'
Add a new method called 'getDateInverse', which just returns: Long.MAX_VALUE - date;
Create my query with: .orderByChild("dateInverse")
Presto! :p
You are searching limitTolast(Int x) .This will give you the last "x" higher elements of your database (they are in ascending order) but they are the "x" higher elements
if you got in your database {10,300,150,240,2,24,220}
this method:
myFirebaseRef.orderByChild("highScore").limitToLast(4)
will retrive you : {150,220,240,300}
In Android there is a way to actually reverse the data in an Arraylist of objects through the Adapter. In my case I could not use the LayoutManager to reverse the results in descending order since I was using a horizontal Recyclerview to display the data. Setting the following parameters to the recyclerview messed up my UI experience:
llManager.setReverseLayout(true);
llManager.setStackFromEnd(true);
The only working way I found around this was through the BindViewHolder method of the RecyclerView adapter:
#Override
public void onBindViewHolder(final RecyclerView.ViewHolder holder, int position) {
final SuperPost superPost = superList.get(getItemCount() - position - 1);
}
Hope this answer will help all the devs out there who are struggling with this issue in Firebase.
Firebase: How to display a thread of items in reverse order with a limit for each request and an indicator for a "load more" button.
This will get the last 10 items of the list
FBRef.child("childName")
.limitToLast(loadMoreLimit) // loadMoreLimit = 10 for example
This will get the last 10 items. Grab the id of the last record in the list and save for the load more functionality. Next, convert the collection of objects into and an array and do a list.reverse().
LOAD MORE Functionality: The next call will do two things, it will get the next sequence of list items based on the reference id from the first request and give you an indicator if you need to display the "load more" button.
this.FBRef
.child("childName")
.endAt(null, lastThreadId) // Get this from the previous step
.limitToLast(loadMoreLimit+2)
You will need to strip the first and last item of this object collection. The first item is the reference to get this list. The last item is an indicator for the show more button.
I have a bunch of other logic that will keep everything clean. You will need to add this code only for the load more functionality.
list = snapObjectAsArray; // The list is an array from snapObject
lastItemId = key; // get the first key of the list
if (list.length < loadMoreLimit+1) {
lastItemId = false;
}
if (list.length > loadMoreLimit+1) {
list.pop();
}
if (list.length > loadMoreLimit) {
list.shift();
}
// Return the list.reverse() and lastItemId
// If lastItemId is an ID, it will be used for the next reference and a flag to show the "load more" button.
}
I'm using ReactFire for easy Firebase integration.
Basically, it helps me storing the datas into the component state, as an array. Then, all I have to use is the reverse() function (read more)
Here is how I achieve this :
import React, { Component, PropTypes } from 'react';
import ReactMixin from 'react-mixin';
import ReactFireMixin from 'reactfire';
import Firebase from '../../../utils/firebaseUtils'; // Firebase.initializeApp(config);
#ReactMixin.decorate(ReactFireMixin)
export default class Add extends Component {
constructor(args) {
super(args);
this.state = {
articles: []
};
}
componentWillMount() {
let ref = Firebase.database().ref('articles').orderByChild('insertDate').limitToLast(10);
this.bindAsArray(ref, 'articles'); // bind retrieved data to this.state.articles
}
render() {
return (
<div>
{
this.state.articles.reverse().map(function(article) {
return <div>{article.title}</div>
})
}
</div>
);
}
}
There is a better way. You should order by negative server timestamp. How to get negative server timestamp even offline? There is an hidden field which helps. Related snippet from documentation:
var offsetRef = new Firebase("https://<YOUR-FIREBASE-APP>.firebaseio.com/.info/serverTimeOffset");
offsetRef.on("value", function(snap) {
var offset = snap.val();
var estimatedServerTimeMs = new Date().getTime() + offset;
});
To add to Dave Vávra's answer, I use a negative timestamp as my sort_key like so
Setting
const timestamp = new Date().getTime();
const data = {
name: 'John Doe',
city: 'New York',
sort_key: timestamp * -1 // Gets the negative value of the timestamp
}
Getting
const ref = firebase.database().ref('business-images').child(id);
const query = ref.orderByChild('sort_key');
return $firebaseArray(query); // AngularFire function
This fetches all objects from newest to oldest. You can also $indexOn the sortKey to make it run even faster
I had this problem too, I found a very simple solution to this that doesn't involved manipulating the data in anyway. If you are rending the result to the DOM, in a list of some sort. You can use flexbox and setup a class to reverse the elements in their container.
.reverse {
display: flex;
flex-direction: column-reverse;
}
myarray.reverse(); or this.myitems = items.map(item => item).reverse();
I did this by prepend.
query.orderByChild('sell').limitToLast(4).on("value", function(snapshot){
snapshot.forEach(function (childSnapshot) {
// PREPEND
});
});
Someone has pointed out that there are 2 ways to do this:
Manipulate the data client-side
Make a query that will order the data
The easiest way that I have found to do this is to use option 1, but through a LinkedList. I just append each of the objects to the front of the stack. It is flexible enough to still allow the list to be used in a ListView or RecyclerView. This way even though they come in order oldest to newest, you can still view, or retrieve, newest to oldest.
You can add a column named orderColumn where you save time as
Long refrenceTime = "large future time";
Long currentTime = "currentTime";
Long order = refrenceTime - currentTime;
now save Long order in column named orderColumn and when you retrieve data
as orderBy(orderColumn) you will get what you need.
just use reverse() on the array , suppose if you are storing the values to an array items[] then do a this.items.reverse()
ref.subscribe(snapshots => {
this.loading.dismiss();
this.items = [];
snapshots.forEach(snapshot => {
this.items.push(snapshot);
});
**this.items.reverse();**
},
For me it was limitToLast that worked. I also found out that limitLast is NOT a function:)
const query = messagesRef.orderBy('createdAt', 'asc').limitToLast(25);
The above is what worked for me.
PRINT in reverse order
Let's think outside the box... If your information will be printed directly into user's screen (without any content that needs to be modified in a consecutive order, like a sum or something), simply print from bottom to top.
So, instead of inserting each new block of content to the end of the print space (A += B), add that block to the beginning (A = B+A).
If you'll include the elements as a consecutive ordered list, the DOM can put the numbers for you if you insert each element as a List Item (<li>) inside an Ordered Lists (<ol>).
This way you save space from your database, avoiding unnecesary reversed data.
How can I exempt a single row in a DataTables.js table from DataTables' builtin filtering, so thta it is always shown?
Background: I'm building a table editing component using the jQuery-based DataTables.js library. Instead of using dialogs or overlays, I wanted to present editing controls right within the datatable, like this:
This works like a charm, even with active filters: I keep the original, unchanged data in the record while it is being edited, so I can use that data for the 'sort' and 'filter' modes of mDataProp, and my row stays in place and visible until editing is finished.
A bigger problem arises when I add a new row: There is no data to use for filtering, so if a filter is active, my row won't be visible. This breaks the workflow where the user searches through the dataset, sees that some record is missing, and (without clearing the filter) presses the "Add" button, waiting for an empty row with edit controls to appear:
How can I exempt this special row from DataTables' filtering?
After reading through the source code of DataTables.js for some time, I came to the conclusion that there is no way to hook into the filtering in the desired way. There are hooks for custom filters, but they can only be used to hide stuff, not to show stuff.
However, there's a 'filter' event which is triggered after filtering, but before the table is rendered. My solution installs an handler for this event:
$('table#mydatatable').bind('filter', function() {
var nTable = $(this).dataTable();
var oSettings = nTable.fnSettings();
//collect the row IDs of all unsaved rows
var aiUnsavedRowIDs = $.grep(oSettings.aiDisplayMaster, function(iRowID) {
var oRowData = nTable.fnGetData(iRowID);
return is_unsaved(oRowData);
});
//prepare lookup table
var oUnsavedRecordIDs = {};
$.each(aiUnsavedRowIDs, function(idx, iRowID) {
oUnsavedRecordIDs[iRowID] = true;
});
//remove unsaved rows from display (to avoid duplicates after the
//following step)
for (var i = oSettings.aiDisplay.length; i >= 0; i--) {
//iterate backwards, because otherwise, removal from aiDisplay
//would mess up the iteration
if (oUnsavedRecordIDs[ oSettings.aiDisplay[i] ]) {
oSettings.aiDisplay.splice(i, 1);
}
}
//insert unsaved records at the top of the display
Array.prototype.unshift.apply(oSettings.aiDisplay, aiUnsavedRowIDs);
//NOTE: cannot just say oSettings.aiDisplay.unshift(aiUnsavedRowIDs)
//because this would add the array aiUnsavedRowIDs as an element to
//aiDisplay, not its contents.
});
What happens here? First, I find all unsaved rows by looking through oSettings.aiDisplayMaster. This array references all rows that are in this DataTable, in the correct sorting order. The elements of aiDisplayMaster are integer indices into DataTables' internal data storage (one index per row).
The filtering process goes through the rows in aiDisplayMaster, and places the row IDs of all matching rows in oSettings.aiDisplay. This array controls which rows will be rendered (after this event handler has finished!). The whole process looks like this:
[1, ..., numRows]
|
| sorting
v
oSettings.aiDisplayMaster
|
| filtering
v
oSettings.aiDisplay
|
| rendering
v
DOM
So after having located all unsaved records in aiDisplayMaster (using custom logic that I wrapped in an is_unsaved() function for the sake of this snippet), I add them all to aiDisplay (after removing existing instances of these rows, to avoid duplicates).
A side-effect of this particular implementation is that all unsaved rows appear at the top of the table, but in my case, this is actually desirable.
I have a grid in ExtJS where I am looping store items. I'd like to find a find to access the item's HTML element, but I'm having hard time finding the way to do this.
Simply put: how do you find the corresponding row HTML element for grid store's one record?
Use its index in the store to retrieve the corresponding row, like so:
var htmlElement = grid.getView().getRow(index);
ExtJS 4.x: grid.getView().getNode(index)
getNode can take an HTML ID (not very useful), an index, or a store record.
Just to add a little to it, if you've got a record that exists in a store that has a grid, but it came from say a separate ajax request, you might do
var objFromJSON: {
id: 134,
name: "Articulated Lorry"
}
var gridIndex = Ext.getStore("myStore").find("id", objFromJSON.id);
var htmlElement = grid.getView().getRow(gridIndex);