I am currently migrating the use of ajax to the fetch, however I am needing a parameter/function the Ajax native beforeSend: function(). I would like to perform the same action without requiring an implementation in fetch (a creation of a new class for example)
jQuery $.ajax structure:
$.ajax({
url: '...',
type: 'post',
data: {...},
beforeSend: function() {
// perform the action..
},
success: function(response, status, xhr) {
// receive response data
}
});
JavaScript fetch structure:
fetch('...').then((response) => {
return response.text();
}).then((data) => {
console.log(data);
});
How do I determine such a function without needing an implementation or creating a new class on fetch. Is there any means or only implementation? because of my searches I only found implementations like CustomFetch (Is there a beforesend Javascript promise) and others.
Solved problem!
No need to implement and/or create a new fetch class. Using only parameters as "function inside function". I hope you can help others!
function ipGetAddress(format) {
requestFetch = function() {
// perform the action..
console.log('** beforeSend request fetch **');
return fetch.apply(this, arguments);
}
requestFetch(`https://api.ipify.org?format=${format}`).then((response) => {
return response.json();
}).then((data) => {
console.log(data.ip);
});
}
ipGetAddress('json') // return local ip address..
Related
I'm trying to load JSON with a JS function, and then make the JSON objects that are loaded available to other functions in the same namespace. I've tried using return to serve up the array of objects retrieved, but that doesn't work. In the attached example, I've assigned the array of objects to a property in the namespaced object, but when I try to get that array of objects outside the main loadData function, all I get is null.
Here's my JS:
var myObj = {
jsonEndPoint: '/test/test.json',
dataObjects: null
}
myObj.loadData = function () {
$.ajax({
url: 'test.json',
type: 'POST',
dataType: 'json',
success: function (data) {
myObj.dataObjects = data.apiResults[0].league.season.draft.rounds[0].picks;
//console.log(myObj.dataObjects);
},
error: function (xhr, textStatus, errorThrown) {
console.log('Data Load Error: ' + textStatus);
}
});
}()
myObj.displayData = function() {
console.log(myObj.dataObjects)
}()
The full example can be seen here: http://zbl.me/test/index.html
The JSON file I'm loading is here: http://zbl.me/test/test.json
That is because JavaScript is asynchronous in nature — when you attempt to access the myObj.dataObjects in the myObj.displayData function, that object does not yet exist because the AJAX call has not been completed yet.
What you could do is that ensure that all functions that require newly added data from the AJAX call be run only when a .done() promise has been delivered from your AJAX call, by using $.when(). The logic is quite straightforward:
myObj.loadData() is now exclusively used to make the AJAX call. With regards to how we handle the done and fail events (which are previously .success() and .error() callbacks), we delegate that logic to the next function.
myObj.displayData() is now use to evaluate the promise returned by your AJAX call made with myObj.loadData(). You use $.when() to fetch the promise, and then simply chain .done() to deal with a successful call and .fail() to deal with the opposite :)
Here's your improved code:
var myObj = {
jsonEndPoint: '/test/test.json',
dataObjects: null
}
myObj.loadData = function () {
// We return the AJAX object so that we can evaluate the state later
// This is very simple :)
return $.ajax({
url: 'test.json',
type: 'POST',
dataType: 'json'
});
}()
myObj.displayData = function() {
// Instead of using the deprecated .success() and .error()
// ... we use .done() and .fail()
$.when(myObj.loadData).done(function(data) {
myObj.dataObjects = data.apiResults[0].league.season.draft.rounds[0].picks;
}).fail(function(xhr, textStatus, errorThrown) {
console.log('Data Load Error: ' + textStatus);
});
}()
If you are unsure, you can check the dummy code here: http://jsfiddle.net/teddyrised/5rbd2eqq/1/ I have used the built-in JSON response from JSfiddle to generate an artificial response, but the logic is exactly the same as yours.
Your displayData method is called even before the ajax is completed. So you either need to call displayData in the success callback of ajax or change the structure a bit so that its easy to call.
Why don't you instead do something like this
var myObj = {
jsonEndPoint: '/test/test.json',
dataObjects: null,
displayData: function() {
console.log(this.dataObjects);
},
loadData: function() {
$.ajax({
context: this,
url: 'test.json',
type: 'GET',
dataType: 'json',
success: function(data) {
this.dataObjects = data.apiResults[0].league.season.draft.rounds[0].picks;
console.log(myObj.dataObjects);
this.displayData();
},
error: function(xhr, textStatus, errorThrown) {
console.log('Data Load Error: ' + textStatus);
}
});
}
};
myObj.loadData();
Here is a demo
I am using $.when and .done to make sure that the close window happens after the data is saved. But, this doesn't seem to work as expected.
The workflow is that, user clicks on a button "Save and Close", which should save the data first, trigger print and close the window. But the save data and close window happens at the same time which makes the print fail.
I have read about when..then and deferred object. Tried to implement it here the following code, sometimes it work but most of the time it would break.
$("#btnSaveAndClose").click(function (event) {
$.when(zSaveSomeData()).done(function (value) {
zCloseMyWindow();
});
});
function zSaveSomeData() {
return zSaveMasterData(masterdata, function () {
return zSaveDetailData();
});
};
function zSaveMasterData(masterdata, fnAfterSave) {
return $.ajax({
type: 'POST',
contentType: 'application/json',
url: '/api/masterdata/',
data: JSON.stringify(masterdata),
success: function (data) {
fnAfterSave();
}
});
};
function zSaveDetailData() {
var selectedDataGroups;
// some logic here
zSaveDetails(selectedDataGroups);
};
function zSaveDetails(selectedDataGroups) {
var deferred = $.Deferred();
$.ajax({
type: 'POST',
contentType: 'application/json',
url: '/api/detaildata/',
data: JSON.stringify(selectedDataGroups),
success: function (data) {
var printableGroupIDs = [];
$.each(data, function () {
if (this.IsPrintable)
printableGroupIDs.push(this.ID);
});
if (printableGroupIDs.length > 0) {
zPrintGroups(printableGroupIDs);
}
deferred.resolve('done');
}
});
zAuditSave();
return deferred.promise();
};
function zPrintGroups(newGroupIDs) {
// calls external program to print groups
};
function zCloseWindow() {
window.close();
};
function zAuditSave() {
$.ajax({
type: 'POST',
contentType: 'application/json',
url: '/api/audit'
success: function (data) {
}
});
};
Only thing is that the save calls other methods inside to same master and details data. There are couple of ajax calls too. An unusual thing is that after the data is saved, there is a call to VB code that actually triggers a Print. I am so confused on why would close window fire before the other methods are executed. Any help would be appreciated.
For me the code is overly divided into functions, with some doing little more than fronting for others.
I would prefer to see the click handler as a comprehensive master routine which sequences three promise-returning functions zSaveMasterData(), zSaveDetails() and zAuditSave(), then closes the window. Thus, some of the current functions will be subsumed by the click handler.
$("#btnSaveAndClose").click(function(event) {
zSaveMasterData(masterdata).then(function() {
var selectedDataGroups;
/* some logic here */
var detailsSaved = zSaveDetails(selectedDataGroups).then(function(data) {
var printableGroupIDs = $.map(data, function (obj) {
return obj.IsPrintable ? obj.ID : null;
});
if (printableGroupIDs.length > 0) {
// calls external program to print groups
}
});
// Here, it is assumed that zSaveDetails() and zAuditSave() can be performed in parallel.
// If the calls need to be sequential, then the code will be slightly different.
return $.when(detailsSaved, zAuditSave());
}).then(function() {
window.close();
});
});
function zSaveMasterData(masterdata) {
return $.ajax({
type: 'POST',
url: '/api/masterdata/',
contentType: 'application/json',
data: JSON.stringify(masterdata),
});
};
function zSaveDetails(selectedDataGroups) {
return $.ajax({
type: 'POST',
contentType: 'application/json',
url: '/api/detaildata/',
data: JSON.stringify(selectedDataGroups)
});
};
function zAuditSave() {
return $.ajax({
type: 'POST',
contentType: 'application/json',
url: '/api/audit'
});
};
Note the returns in the three functions with ajax calls. These returns are vital to the sequencing process.
A potentially bigger issue, not addressed in the question (nor in this answer) is how to recover from errors. Presumably, the database will be inconsistent if the sequence of saves was to fail part way through. It may well be better to ditch this client-side sequencing approach in favour of a server-side transaction that the client sees as a single operation.
The problem here is your code doesn't depend on when fnAfterSave() has completed.
Short answer: don't mix success methods, callbacks, and promises - use one pattern and stick to it - and the easiest pattern to use is promises.
$("#btnSaveAndClose").click(function (event) {
zSaveSomeData().then(function() { zCloseMyWindow(); });
});
function zSaveSomeData() {
return zSaveMasterData(masterdata).then(function(data) { zSaveDetailData() });
};
function zSaveMasterData(masterdata) {
return $.ajax({
type: 'POST',
contentType: 'application/json',
url: '/api/masterdata/',
data: JSON.stringify(masterdata)
});
//remove success callback here as it breaks the chaining
};
It seems like your problem is that you are doing asynchronous things inside an ajax success callback. The promise returned by $.ajax still resolves immediately after the response is received - and executes your done callback before the asynchronous zSaveDetailData() has finished.
So, to chain asynchronous actions, always use then. Use it even for synchronous actions, it makes the sequence clear.
Don't use success callbacks when you're working with promises. You also don't need deferreds. You might want to have a look at these generic rules as well, especially that you never must forget to return promises from async functions that you want to await.
$("#btnSaveAndClose").click(function (event) {
zSaveSomeData().then(zCloseMyWindow);
});
function zSaveSomeData() {
return zSaveMasterData(masterdata).then(zSaveDetailData);
}
function zSaveMasterData(masterdata) {
return $.ajax({
type: 'POST',
contentType: 'application/json',
url: '/api/masterdata/',
data: JSON.stringify(masterdata),
});
}
function zSaveDetailData() {
var selectedDataGroups;
// some logic here
return zSaveDetails(selectedDataGroups);
// ^^^^^^
}
function zSaveOrderGroups(selectedDataGroups) {
return $.ajax({
// ^^^^^^
type: 'POST',
contentType: 'application/json',
url: '/api/detaildata/',
data: JSON.stringify(selectedDataGroups)
}).then(function(data) {
// ^^^^^^^^^^^^^^^^^^^^^^
var printableGroupIDs = [];
$.each(data, function () {
if (this.IsPrintable)
printableGroupIDs.push(this.ID);
});
if (printableGroupIDs.length > 0) {
return zPrintGroups(printableGroupIDs);
// ^^^^^^
}
}).then(zAuditSave);
// ^^^^^^^^^^^^^^^^^
}
function zPrintGroups(newGroupIDs) {
// calls external program to print groups
}
function zCloseWindow() {
window.close();
}
function zAuditSave() {
return $.ajax({
// ^^^^^^
type: 'POST',
contentType: 'application/json',
url: '/api/audit'
});
}
I have looked at various questions that talk about when Synchronous requests, how to return data from the Ajax request (with Promises and Callbacks) but nothing seems to answer what I am after.
var FacadeApi = ( function($) {
var endpoint = '/auth/',
self = this,
settings = {
isAuthenticated: false,
authkey: null
};
function init() {
$.ajax( {
url: self.endpoint,
dataType: 'json',
async: true
})
.done( function( `enter code here`data ) {
self.settings.authKey = data.authKey;
self.settings.isAuthenticated = true;
})
.fail( function( error ) {
});
}
var Facade = {
someRequest: function( ) {
$.ajax( {
url: someUri,
dataType: 'json',
data: { authKey: authKey }
})
.done( fuction( data ) {
// does stuff.
});
}
};
init();
return Facade;
}( jQuery ));
My module depends on requesting an authentication key and then having that as part of each request. Until this request is resolved, it can't be used. Which lead me to the async: false in the init function.
In this scenario, is it recommended to 'block' until the init call is completed? Could I achieve what I am after and keep the init request asynchronous?
So if i understand correctly,
You want to make sure that if someone calls somerequest() it should wait till you have the token , which is initiated in a separate request.
I suggest following pattern.
Do not call init() from the beginning.
when you need to call somerequest()
check if you have valid token value.
If token value is not there you can use $.When() such that somerequest() is only called when init() ajax call returns successfully.
If I have to leverage niceties of jQuery AJAX API and set my own custom settings for each ajax call my app makes like below:
Say I have a page which displays employee information within table by making ajax calls to some API.
define(["jQuery"], function($) {
var infoTable = function (options) {
function init() {
// Provide success callback
options.success_callback = "renderData";
getData();
}
function renderData() {
// This callback function won't be called as it is not
// in global scope and instead $.ajax will try to look
// for function named 'renderData' in global scope.
// How do I pass callbacks defined within requirejs define blocks?
}
function getData() {
$.ajax({
url: options.apiURL,
dataType: options.format,
data: {
format: options.format,
APIKey: options.APIKey,
source: options.source,
sourceData: options.sourceData,
count: options.count,
authMode: options.authMode
},
method: options.method,
jsonpCallback: options.jsonpCallback,
success: options.success_callback,
error: options.error_callback,
timeout: options.timeout
});
}
}
return {
init: init
}
}
How do I achieve this?
I know we can use JSONP request as require calls but that restricts me to using jsonp, making GET requests and all other features $.ajax offers.
This example would let you either use a default success callback, or provide an override, using:
success: options.successCallback || renderData
(The example uses jsfiddle rest URLs - this fact is unimportant, and stripped out the data object to keep the example short)
define("mymodule", ["jquery"], function($) {
function renderData() {
console.log("inside callback");
}
function getData(options) {
$.ajax({
url: options.apiURL,
dataType: options.format,
method: options.method,
jsonpCallback: options.jsonpCallback,
success: options.successCallback || renderData,
error: null,
timeout: options.timeout
});
}
return {
getData: getData
}
});
require(["mymodule"], function(m) {
console.log(m, m.getData({
apiURL: "/echo/json/"
}));
console.log(m, m.getData({
successCallback: function() { console.log("outside callback"); },
apiURL: "/echo/json/"
}));
});
Would print:
GET http://fiddle.jshell.net/echo/json/ 200 OK 263ms
Object { getData=getData()} undefined
GET http://fiddle.jshell.net/echo/json/ 200 OK 160ms
Object { getData=getData()} undefined
inside callback
outside callback
I'm trying to trigger an action after a Javascript object has been created via an AJAX call. My object looks something like this:
function API(uid,accessToken){
$.ajax("path/to/file", {
type: "POST",
data: { user: uid, auth: accessToken },
dataType: "json",
success: function(jsonData) {
arrayname = jsonData[values]
}
});
}
I tried to use JQuery's $.when function to do a callback after the object setup is complete (ie. the array is populated with the ajax response), which looked like this:
$.when( API = new API(uid, accessToken) ).then(function() {
...success function...
});
...but the $.when function triggers with the arrayname values still undefined. From the function's standpoint the deferred object is resolved even though the object values have not yet been set. I've since tried a number of ways to make the API object become deferred based on the completing of the entire ajax call and the setting of the variables, but I'm a bit stuck on the best way to do this.
Any pointers would be most appreciated! Thanks.
You could pass the callback function when you create the object, like so:
function API(uid,accessToken, callback){
$.ajax("path/to/file", {
type: "POST",
data: { user: uid, auth: accessToken },
dataType: "json",
success: function(jsonData) {
arrayname = jsonData[values]
callback(jsonData[values])
}
});
}
and then instantiate the object like so
var api = new API(uid, accessToken, function(array) {
// success function
});
If the problem is due to the "success" callback running after the "then" callbacks, you could try turning success callback into a then callback as well. I don't use JQuery but I guess it would look something like:
function API(uid,accessToken){
return $.ajax("path/to/file", {
type: "POST",
data: { user: uid, auth: accessToken },
dataType: "json",
}).then(function(jsondata){
arrayname = jsondata[values]
});
}
$.when( API = new API(uid, accessToken) ).then(function() {
// ...
});
The reason you use $.when is when you are correlating the callbacks of multiple promises, async tasks, etc. Since jQuery 1.5, all calls to $.ajax and all the wrappers ($.get and $.post) all return promises. Therefore you don't need to wrap this call with the $.when statement unless you want to do $.when(ajaxCall1, ajaxCall2).
Since you want to filter the result from the server, you should use the pipe method of promises:
function API(uid, accessToken)
return $.post(
type: 'POST'
,data: { user: uid, auth: accessToken }
,dataType: 'json'
)
.pipe(function(json) {
return json[values];
})
;
}
This allows you to write your code the way you desire:
API(uid, token)
.then(
// success state (same as promise.done)
function(arrayname /* named from your sample script*/) {
alert('success! ' + arrayname);
}
// error state (same as promise.fail)
,function(jqXHR, status, error) {
console.warn('oh noes!', error);
}
)
.done(function() { /* done #2 */ })
.fail(function() { /* fail #2 */ })
;
Note: promise.pipe() also allows you to filter (change the data passed to) the error callback as well.