I'm using Select2 4.0.3 with remote data and server paging and it is working fine. The data returned from the api has additional fields, something like this:
var data = {
id: 12345,
text: 'John Doe',
email: 'abc#123.com'
}
According to the documentation here is the example of how to pre-select an option when using remote data, which also works fine (with one issue as noted below):
$.ajax({
type: 'GET',
url: '/api/students/s/' + studentId
}).then(function (data) {
// create the option and append to Select2
var option = new Option(data.full_name, data.id, true, true);
studentSelect.append(option).trigger('change');
// manually trigger the `select2:select` event
studentSelect.trigger({
type: 'select2:select',
params: {
data: data
}
});
});
The documentation explains about the last bit:
Notice that we manually trigger the select2:select event and pass
along the entire data object. This allows other handlers to
access additional properties of the selected item.
In my case the additional property is the email field.
My question/problem is that for the above 'manually' appended option the select2 JSON data has only the id and text fields. If the user clicks the list and allows it to populate the data from the server then the data has the id, text, and email fields as it should.
The documentation statement explaining why the trigger was needed indicates to me that the data object returned from the api would be passed on (and presumably used), but this does not seem to be the case.
So in my case leaving out or including the trigger portion has no effect of the control, so am I misunderstanding the purpose of that code or is select2 not working as documented?
For Example, in the templateSelection function used to format the control selection, which is called when the append and trigger code is executed, the object passed to the function has only the id and text properties. In fact if the original data object had completely different properties, say name, value, and email, the data object passed to the function still has id and text only, which is the default object used by select2. This behaviour forced me to modify the object to conform to the {id, text} pattern.
Related
Application is using:
DataTables 1.10.18
jquery 3.2.1
PHP back-end
lodash 4.17.4
The application contains a web page which consists of multiple DataTables. Each of these uses serverSide: true (server-side mode) to obtain the data via an ajax endpoint which returns JSON data.
The tables are initialised as follows:
On page load several <table>'s are rendered. I'm using a jquery .each() to initialise the DataTable for each one:
$.each($('table'), function () {
$(this).DataTable({
processing: true,
serverSide: true,
searching: false,
ajax: {
data: {
table_id: $(this).attr('id')
},
url: '/get-data.json',
},
...
});
Each <table> has an ID. This is passed via ajax in the data: attribute. The endpoint /get-data.json returns data based on the table ID. In other words it knows "which table" the data should be obtained for based on this ID.
I want to be able to do searching on tables, but it must be done server-side. For this reason my initialisation code in (1) sets searching: false because this effectively disables the client-side search facility that DataTables provides (which we can't use in this instance as searching must be done server-side).
The problem I'm facing is how to create search inputs for each table, make an ajax call and update the appropriate table. I want the search to work in realtime after >=3 characters have been entered. Critical to this question is that 1 search input is responsible for searching 1 DataTable - it's not a search feature where the input can update "any/every table on the page" which is a commonly described pattern in other questions. 1 input : searching 1 table in this case.
My plan has been as follows - each table referenced in point (2) has an ID. I need to create unique inputs. So if I have tables with ID's #table1, #table2, #table3 I can easily create:
<input type="text" name="table1_search" id="table1_search">
<input type="text" name="table2_search" id="table2_search">
<input type="text" name="table3_search" id="table3_search">
I then detect if any changes have occurred on inputs:
$('input[type="text"]').bind("keyup change input",
function (e) {
// Ignore tab key for keyup event otherwise it'll fire an ajax request that does nothing useful.
if (e.which !== 9) {
processSearch.call(this);
} else {
e.preventDefault();
}
});
var prev_value = {};
function processSearch() {
var obj = $(this),
search_id = obj.attr('id'), // ID of input
search_value = obj.val(); // Value of input
// There's been no change to the field, ignore.
if (prev_value[search_id] === search_value) {
return;
}
prev_value[search_id] = search_value;
/* Wait until at least 3 characters have been entered, or user has cleared the input */
if (search_value.length >= 3 || (!search_value)) {
debouncedDraw({search_id: search_id, search_value: search_value});
}
}
The above code does what I need in terms of waiting for >=3 characters to be entered. I'm then executing a function called debouncedDraw which passes an object containing search_id and search_value. These refer to the input ID and value respectively, e.g. if I type "foo" into #table1_search then the object is:
{search_id: 'table1_search', search_value: 'foo'}
The debouncedDraw function looks like this. This is using lodash to limit the rate at which the function can fire. The point here is to stop it making needless ajax requests based on a question I asked a few years ago here: DataTables - kill ajax requests when a new one has started:
var debouncedDraw = _.debounce(function (opts) {
console.log(opts);
}, 500);
At the moment this will just console.log the object given above.
I'm unsure of the best way to proceed at this point. I need to re-run /get-data.json via ajax and then update the appropriate table.
I could access the request data and split the search_id based on the underscore to work out which table ID the data is for (e.g. table1_search targets #table1). I then need to write this data back to the appropriate table (#table1 in this case).
I can't help but think I'm going about this in a convoluted way and wondered if DataTables itself has any better ways of supporting this? It seems quite a basic requirement (multiple searchable tables in serverSide mode). But I can't find any posts which refer how to do this specifically.
All the "gotchas" I've experienced over the years is encapsulated in the snippet below. This is the basic template I always use when creating a new datatable. You can create as many datatables on a page as you need using this pattern.
Personally I would use a different ajax url path/route for each table so that table logic is in separate files in the backend... but it is possible to have all the data logic in a single backend file. I modified my usual template to suit that.
<script> //I usually put the script section in the head tag
var table_1; //declare your table var here and initialize as a datatable inside document ready below.
$(document).ready(function() {
table_1 = $('#table_1').DataTable( {
dom: "Bfrtip",
ajax: {
url: "/get-data.json?table=table_1", //add query string var for backend routing
type: "POST" //use POST to not have to deal with url encoding various characters
},
serverSide: true,
searchDelay: 2000, // use this instead of custom debounce
processing: true, // optional visual indicator that a search has been sent to backend
lengthMenu: [ 10, 25, 50, 75, 100 ], // define per page limits. first value will be the default
buttons: [
"pageLength" // per page drop down button. i usually override/extend the default button
],
columns: [ // column definitions of json data fields
{ data: "col_1", title: "ID", width: "1%" }, // width: 1% makes col width as small as possible
{ data: "col_2", title: "Label 2", visible:false }, //visible: false allows you access to field data without displaying to user
{ data: "col_3", title: "Label 3", render: function ( data, type, row ) { //render allows combining of fields into single column
return data + ' <small>('+row.col_2+')</small>'; // data will be col_3 value. row.col_2 is how you reference col_2 value
} },
{ data: "col_4", title: "Label 4", searchable:false }, //searchable: false set this field to not be used in search
],
rowId: 'col_1' //sets the tr row id to the value in this column. useful for DOM and other manipulation later
} );
}
</script>
<table id="table_1" class="table table-striped table-bordered table-sm" style="width:100%"></table>
<!-- If you define title attributes in col definitions above you don't need to create html table headers/footers. Just an empty table tag will do. -->
With this pattern you can utilize the built-in search input that comes with datatables for your use case with server-side processing on all tables.
There's a method behind my madness which I tried to document in the script comments on each line. Let me know if you have a question on something. I'm thinking this is bounty worthy.
For reference, when developing a new app using datatables I basically live on this page https://datatables.net/reference/option/
Edit 1
Inside your existing debounced drawTable function you could do something like this:
function drawTable(id) {
$('#'+id).DataTable().ajax.url( 'get-data.json?table_id='+id+'&foo=bar' ); //update ajax url of existing dt - if necessary
$('#'+id).DataTable().search(search_input_val).draw(); // fire ajax request with value from your custom search input
}
I'm fairly certain you will need to set "searching" to true though for this method to work.
Edit 2
Another way I just thought of, without using dt search. Pass all your data through modified url and load/reload.
$('#'+id).DataTable().ajax.url( 'get-data.json?table_id='+id+'&search=foo' ).load();
You could then get rid of all the debounce stuff if you use a button click listener or an onblur listener on the input field and fire the same command above.
Have you seen this? https://datatables.net/reference/api/%24.fn.dataTable.util.throttle()
I've never used it before, but it looks like a debounce. The example on the page shows it being used for .search()
I've implemented the following but would prefer a better solution as I don't think this is efficient and it definitely isn't elegant!
Taking the code from the question I modified the debounce function as follows:
var debouncedDraw = _.debounce(function (opts) {
// Destroy the existing DataTable.
$('#' + opts.search_region).DataTable().destroy();
// Re-run the drawTable method to get the new DataTable with the search results
drawTable(opts.search_region);
}, 500);
I introduced a function called drawTable which takes the ID of a <table> and runs the DataTables initialisation code. The ajax object was also modified to take into account anything entered into the search keywords input for the given table ID:
function drawTable(id) {
$id = $('#'+id); // Convert string ID to jquery identifier
$id.DataTable({
// DataTable initialisation code as per question
ajax: {
data: {
table_id: id,
keywords: $('input[name="keywords_' + id + '"]').val() // search keywords for table_id
},
url: '/get-data.json',
},
// ... code as per question
});
}
The $.each() was modified so that it detects the ID of each <table> on page load and calls drawTable:
$.each($('table'), function () {
drawTable($(this).attr('id'));
});
This "works" in that it creates each of the required DataTable's on page load, and also handles the search. The search input names were modified to the format: keywords_ plus the ID of the table, e.g. keywords_table1.
I don't think this is efficient because I'm having to call destroy on my DataTable. As per the docs:
This has a very significant performance hit on the page, since a lot of calculations and DOM manipulation is involved, so if you can avoid this, and use the API, that is very strongly encouraged!
However the reason I'm doing this is also as given in the same docs:
DataTables does not allow initialisation options to be altered at any time other than at initialisation time. Any manipulation of the table after initialisation must be done through the API
Well, I'm not using the client-side search feature as I'm having to do searching server-side. So I'm unsure whether manipulating the table via the API would actually help in this instance anyway.
Are there better ways of achieving this?
I have 2 cascading drop down list , when page loads, data is loaded to the 1st DDL, when item is selected from this list its goes to the database and fetch matching items and populate 2nd DDL. I want to prevent going twice to the DB on selection.
For example, I am loading 1st DDL with cars manufactures then click on Toyota what happens next is it goes to DB and fetches all Toyota's models and populates the 2nd DDL, after that i select different car manufacture, same thing happens. Now when i select again Toyota from the 1st list it will not go to DB, it will pull the data from previous request.
I will like to keep an object (like dictionary) of the requests, so if item is already been requested it will not go back to the DB but use local saved data.
You can store list return from server through LocalStorage in Javascript. By using setItem()function as shown below.
window.localStorage.setItem('Toyota', 'Models');
Where Toyota is the key and Models is the value. Also note that LocalStorage can only store strings.
To store arrays or objects you would have to convert them to strings.
To do this we use the JSON.stringify() method before passing to setItem() .
const models = {
1: "Model-1",
2: "Model-2",
}
window.localStorage.setItem('Toyota', JSON.stringify(models));
Now when ever you select different car manufacture check its value in LocalStorage object first.
It accepts only one parameter which is the key and returns the value as a string.
To retrieve the Toyota key stored above:
window.localStorage.getItem('Toyota');
This returns a string with value as.
“{“1”:”Model-1”,”2”:”Model-2”}”
To use this value, you would have convert it back to an object.
To do this, we make use of JSON.parse() method which converts a JSON string into a Javascript Object.
JSON.parse(window.localStorage.getItem('Toyota'));
Please keep in mind to check weather your browser support Local storage or not.
if (typeof(Storage) !== "undefined") {
// Code for localStorage
} else {
// No web storage Support.
}
You can use Map() object to store the data based on key.
Find more information: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map
var brandModelsList = new Map();
function getBrandModels(brand)
{
if(brandModelsList.has(brand))
{
modelList = JSON.parse(brandModelsList.get(brand));
// Do stuff with second dropdown
}
//Your ajax stuff to get data
$.ajax({
url: 'server url',
data: {name: brand},
dataType: 'json',
}).done(response => {
brandModelsList.set(brand, JSON.stringify(response));
// Do stuff with second dropdown
});
}
It has support in most of modern browsers. A best tutorial on this is https://javascript.info/map-set-weakmap-weakset.
you can do this via JavaScript as #Rahat Hameed stated if the cascading dropdown values are not changed frequently, if they can be changed e.g (you can updated them via some logic).Then preferable ways it to fetch them from database.
I'm working on creating an interface for some system I am working on and I am required to write the Javascript around pre-existing PHP AJAX functions that are used elsewhere in the system (purely as the person who does our DB stuff is too busy to adapt the code to my needs).
Using Select2 I need to make a select field where the user searches for their name in the database and selects the one matching it so it can then be posted to another AJAX function later. I have done this with the following code:
//<select id="sltMyName" style="width: 100%;"></select>
$("#sltMyName").select2({
ajax: {
type: "POST",
url: "includes/php/report_searchPlayers.php",
delay: 250,
data: function (params) {
return {
q: params.term // search term
};
},
processResults: function (data) {
console.log({ results: data.split(",") });
return { results: data.split(",") };
}
},
minimumInputLength: 1
});
This should turn a returned string in the format of name1,name2,name3,name... into the required format for Select2 to display, however, it does not currently work. The dropdown just appears blank.
I've seen some questions referring to a text and id attribute, however, they are all in the context of a JSON string being returned, so I am not sure if they are required here and how to utilise them in this context. Furthermore, I cannot find any of this in the documentation.
Any suggestions? Thanks in advance.
Data returned:
Tommy,Jak_Tommy_Lee_Jones,Tommy_Shelby,Tommy_Balboner,TommyCZ,GA_Tommy,VA_Tommy,Tommy_Skrattar,Tommy_Knocker,Tommy_of_Elektro,Tommy_the_Destroyer,Old_Tommy,tommy_of_house_shelby,TommyDermo,TommyC,TommyCash_CZ,Tommyb69k,SA_Tommy,tommyfaster,Tommy_See,Tommy_de_Destroyer,Tommy_of_Whiteroses,TommyShelby,Templar_Intiate_Tommy,Templar_Initiate_Tommy,tommysuckspp,Tommy_the_Overweight
I think I've figured it out. The main issue is that the data that Select2 wants to use needs to be an array of objects with at least a property named id and a property named text. In the processResults function, just create those objects & then the dropdown will populate with the data from your URL!
I've noticed that it tries to filter the data as i type, but since the url I passed in does not accept the parameters, it just returns the same data each time. Let me know if you need a more robust example.
See my fiddle at https://jsfiddle.net/yp0rp2kw/3/ for a working solution.
I have a form that consists of a number of multi-select fields. Each select has a unique ID, and are named accordingly:
values[foobar1][]
values[foobar2][]
values[foobar3][]
... etc.
This form could potentially contain hundreds of these fields, and so is paged by ajax. The result of that is that there is no guarantee that all records are going to available at once at the front end. Therefore, it is impossible for me to submit the entire form. I do, however, have access to the entire list of records server-side.
My solution to this was to watch for changes in the form fields and, for every field that is changed, store the values in an array to keep track of just the altered field values. So if you make a change to just foobar2, the resulting serialized array that is sent to the server will look like this:
0: Object {
name: "values[foobar2][]"
value: "thevalue1"
},
1: Object {
name: "values[foobar2][]"
value: "thevalue3"
}
So this works fine except for, as you may have guessed, when the select multiple is emptied. No matter what format I use for storing the altered values, be it arraySerialization of each field or as an associative array, when I pass my array to $.param() for the ajax request the resulting serialized string contains no trace of the empty value. So there is no way for the server to determine that the value has been emptied.
Can anyone suggest a way of either passing the data to the server so that the empt(ied) array remains intact, or another way of dealing with the initial problem.
Thanks in advance!
You want to calculate the diff between current and previous state, send the change to the server, and apply it to the data.
You can do so using the JSON patch standard (rfc6902).
JSON Patch is a format for describing changes to a JSON document. It
can be used to avoid sending a whole document when only a part has
changed. When used in combination with the HTTP PATCH method it allows
partial updates for HTTP APIs in a standards compliant way.
To create the diff you can use an NPM module, such as jiff. A diff is set a of patching commands, that can transform a JSON document. For example:
[
{ "op": "replace", "path": "/values/foobar2/", "value": ["thevalue1"] },
{ "op": "remove", "path": "/values/foobar2/"}
]
You send the diff to the server, and then use a server module, such as php-jsonpatch, to apply the patch to the current data on the server.
Create a single object for all select field values you can use localStorage or sessionStorage to store it. Since the form is in a lot of pages and you use ajax to get each select field. Place the selected values of each field in an array. Creating an object like this is the idea.
{
formValues: {
foobar1: {
values: ["thevalue1","thevalue2"]
},
foobar2: {
values: ["thevalue3"]
},
...
foobarN: {
values: []
}
}
}
Every time you update a select vield value or values make sure to update the localStorage saved value. e.g.
var valuesObject = {
formValues: {
foobar1: {
values: ["thevalue1","thevalue2"]
},
foobar2: {
values: ["thevalue3"]
},
foobar3: {
values: []
}
}
}
// Put the object into storage
localStorage.setItem('valuesObject', JSON.stringify(valuesObject));
// Retrieve the object from storage
var valuesObjectA = localStorage.getItem('valuesObject');
//console.log('valuesObject: ', JSON.parse(valuesObjectA));
// post your data
$.post( "ajax.php", valuesObjectA ).done(function( data ) {
alert( "Data Loaded: " + data );
}).fail(function() {
console.log( "error" );
});
Sample fiddle
I am attempting to retrieve the information for a Model and an associated model that contains a hasOne association. I was referencing the following Sencha documentation page (http://docs.sencha.com/ext-js/4-1/#!/guide/data). I currently have the following sample code working:
var Mtd = Ext.ModelMgr.getModel('Mtd');
Mtd.load(4, {
success: function(mtd){
console.log("Loaded! " + mtd.get('id'));
mtd.getTreatmentdesign(function(treatment,operation){
console.log(treatment.get('id'));
}, this);
}
});
Now, when I call mtd.getTreatmentdesign(), I notice that two requests are made to retrieve information. The first one is to retrieve the Mtd information which I am expecting but then it's also making a request to retrieve the Treatmentdesign information. The response for the Mtd contains the Mtd information as well as the Treatmentdesign information. So I want to process the Mtd and Treatmentdesign information with one request. It puzzled me that the documentation stated the following:
You may be wondering why we passed a success function to the User.load call but didn't have to do so when accessing the User's posts and comments. This is because the above example assumes that when we make a request to get a user the server returns the user data in addition to all of its nested Posts and Comments. By setting up associations as we did above, the framework can automatically parse out nested data in a single request.
So how can I retrieve associated information without having to make another request? I simply just want to use all the json from a single request as opposed to having to make multiple requests.
Be sure to set the associationKey config on the HasOne association to the property that contains the data for the associated model. By default, this is the name of the associated model class in all lowercase letters.
For instance, if the data for an Mtd record is returned by the server in the form
{
...
treatmentDesign: {
...
}
}
set the associationKey to 'treatmentDesign'.
Here's an example in action: http://jsfiddle.net/HP6fq/3/
Yes, associationKey works
Ext.define('User', {
extend:'Ext.data.Model',
fields: ['id', 'name', 'status'],
associations: [{ type: 'hasOne', model: 'Status', associationKey: 'status' }]
});
Ext.define('Status', {
extend:'Ext.data.Model',
fields: ['id', 'title'],
});
Demo here