I'm working on creating a Users collection with the ability to then grab single users inside. This will be used to match from another system, so my desire is to load the users once, and then be able to fine/match later. However, I'm having a problem accessing the outer users collection from an inner method.
function Users(){
var allUsers;
this.getUsers = function () {
// ajax to that Jasmine behaves
$.ajax({
url: '../app/data/jira_users.json',
async: false,
dataType: 'json',
success: function(data) {
allUsers = data;
}
});
return allUsers;
};
this.SingleUser = function (name) {
var rate = 0.0;
var position;
this.getRate = function () {
if(position === undefined){
console.log('>>info: getting user position to then find rate');
this.getPosition();
}
$.ajax({
url: '../app/data/rates.json',
async: false,
dataType: 'json',
success: function(data) {
rate = data[position];
}
});
return rate;
};
this.getPosition = function () {
console.log(allUsers);
//position = allUsers[name];
return position;
};
//set name prop for use later I guess.
this.name = name;
};
}
and the test that's starting all of this:
it("get single user's position", function(){
var users = new Users();
var someone = new users.SingleUser('bgrimes');
var position = someone.getPosition();
expect(position).not.toBeUndefined();
expect(position).toEqual('mgr');
});
The getPosition method is the issue (which might be obvious) as allUsers is always undefined. What I have here is yet another attempt, I've tried a few ways. I think the problem is how the Users.getUsers is being called to start with, but I'm also unsure if I'm using the outer and inner vars is correct.
Though the others are correct in that this won't work as you have it typed out, I see the use case is a jasmine test case. So, there is a way to make your test succeed. And by doing something like the following you remove the need to actually be running any kind of server to do your test.
var dataThatYouWouldExpectFromServer = {
bgrimes: {
username: 'bgrimes',
show: 'chuck',
position: 'mgr'
}
};
it("get single user's position", function(){
var users = new Users();
spyOn($, 'ajax').andCallFake(function (ajaxOptions) {
ajaxOptions.success(dataThatYouWouldExpectFromServer);
});
users.getUsers();
var someone = new users.SingleUser('bgrimes');
var position = someone.getPosition();
expect(position).not.toBeUndefined();
expect(position).toEqual('mgr');
});
This will make the ajax call return whatever it is that you want it to return, which also allows you to mock out tests for failures, unexpected data, etc. You can set 'dataThatYouWouldExpectFromServer' to anything you want at any time.. which can help with cases where you want to test out a few different results but don't want a JSON file for each result.
Sorta-edit - this would fix the test case, but probably not the code. My recommendation is that any time you rely on an ajax call return, make sure the method you are calling has a 'callback' argument. For example:
var users = new Users();
users.getUsers(function () {
//continue doing stuff
});
You can nest them, or you can (preferably) create the callbacks and then use them as arguments for eachother.
var users = new Users(), currentUser;
var showUserRate = function () {
//show his rate
//this won't require a callback because we know it's loaded.
var rate = currentUser.getRate();
}
var usersLoaded = function () {
//going to load up the user 'bgrimes'
currentUser = new users.SingleUser('bgrimes');
currentUser.getRate(showUserRate);
}
users.getUsers(usersLoaded);
your approach to fill the data in allUsers is flawed
the ajax call in jquery is async so every call to users.getAllUsers would be returned with nothing and when later the success function of the jquery ajax is called then allUsers would get filled
this.getUsers() won't work. Its returning of allUsers is independent from the ajax request that fetches the data, because, well, the ajax is asynchronous. Same with getRate().
You'll have to use a callback approach, where you call getUsers() with a callback reference, and when the ajax request completes, it passes the data to the callback function.
Something like:
this.getUsers = function (callback) {
// ajax to that Jasmine behaves
$.ajax({
url: '../app/data/jira_users.json',
async: false,
dataType: 'json',
success: function(data) {
callback(data);
}
});
};
And the call would be along the lines of:
var user_data = null;
Users.getUsers(function(data) {
user_data = data;
});
Related
I'm trying to pass a parameter from a onload GET method call to a POST method. The GET method is being loaded on window.onload and the POST function is not in the onload call otherwise the POST function will trigger once the window has loaded. I only want to trigger POST function when I click a button.
How can I pass a variable from a onload AJAX call to my POST function?
The only way I could think of is using a global variable however I don't think that's a good way of passing it to another function.
window.onload = function () {
function firstCallBack() {
$.get('http://website.com/API/docs/v1').then(function(data1){
var passThis = "PassMeToPOST"
}).then(function (data2) {
})
}
}
POST function
function saveSettings(passThatVar) {
var urlVal = window.__env.url+ "Preview/TypeDefinition";
var xslSettingVal = $('#PreviewXml').val().replace(/\n/g, "");
var allData = {
'ObjectName': passThatVar,
'DisplayDefinition': setting,
}
$.ajax({
url: urlVal,
type: "POST",
data: JSON.stringify(allData),
success: function (data) {
console.log('success');
}
});
}
Button HTML:
<button onclick="saveSetting()"> Save Setting </button>
Try this:
Your button:
<button id="save-settings"> Save Setting </button>
After your get request, set a data-attribute to your button:
function firstCallBack() {
$.get('http://website.com/API/docs/v1').then(function(data1){
$("#save-settings").data("passMe", "PassMeToPOST");
}).then(function (data2) {
})
}
Bind the click event(its a best practice than using inline events):
$("#save-settings").on("click", saveSetting);
On your saveSetting() function:
function saveSetting() {
var allData = {
'ObjectName': $(this).data("passMe"),
'DisplayDefinition': setting,
}
//... your post request
}
You can also check if the get request has finished before starting the post request(to avoid a bug in an extreme scenario):
if (!$(this).data("passMe")) {
return;
}
You're basically asking how to keep a variable out of the global scope. This is called encapsulation. It is a good instinct but a large topic. Here is a post that I like on the topic: http://javascriptissexy.com/oop-in-javascript-what-you-need-to-know/
One low budget way of doing this is instead of making a global variable for your value, make a global namespace for your own use.
var MyUniquelyNamedThing = {};
...
// get response:
MyUniquelyNamedThing.ThatValueINeed = data;
...
// posting:
data = { val1: MyUniquelyNamedThing.ThatValueINeed , etc. };
I have a question about a problem I am bumping into. I am using AngularJS as my framework and do not have access to jQuery nor Lodash.
The problem
I have a function called "refresh". That function makes an async call via angular $http to get new data from the server. The server only gives 25 new updates to me from the date I specify. So to get all the new messages I need to call the server (and update the "updateDate" everytime I get data) until it tells me that it has no more messages (empty array).
Code example
$scope.refresh = function () {
var date = new Date();
$http({
method: 'GET',
url: 'http://path.to.my.server',
timeout: 6000
}).then(function (success) {
date = success.date[0].date; //0 is always the newest message
callback(success.data);
//Do some stuff with the data
}, function (error) {
console.error("Could not retrieve new messages: \n", error.data);
errcallback(error);
});
}
What I have tried
I have tried to get set the request in a separate function and make calls to it like you would do with a normal a-sync function.
I have also tried a while loop and setting a boolean when I am done with collecting. The only problem is that a while loop doesn't wait for the call to end (otherwise it wouldn't be async) and makes quite an impressive loop (not yet infinite, but enough to crash my program).
I was thinking about a for loop, but I do not know how much iterations I should make. It could be 1 but also could also be 5 or more.
I know how recursive functions work, but I do not know how I should use an async recursive function. Any advice or solutions are welcome. (I won't have to be recursive if anyone knows an other solution)
There's nothing particularly special about making async functions recursive, you just don't have to worry about running out of stack.
Just isolate your ajax call into a function, and have that function call itself until it has a complete picture of the data:
$scope.refresh = function () {
var date = new Date();
var results = [];
gather();
function gather() {
$http({
method: 'GET',
url: 'http://path.to.my.server',
timeout: 6000
// presumably using `date` here?
}).then(function(success) {
// This seems to assume you'll always have at least
// one row, which doesn't seem to match with your description
date = success.data[0].date; //0 is always the newest message
if (thereAreNewResults) {
results.push.apply(results, success.data);
gather();
} else {
// We're done
callback(results);
}
}, function (error) {
console.error("Could not retrieve new messages: \n", error.data);
errcallback(error);
});
}
};
That's not meant to be full-formed and perfect, but it should send you in the right direction.
Note my if (thereAreNewResults). I would have thought that would be if (success.data.length) but the code in your question seemed to suggest there'd always be at least one row, so adjust as appropriate.
I will make a recursive function who get the data :
$scope.refresh = function () {
$scope.allDatas = [];
var getData = function(date){
$http({
method: 'GET',
url: 'http://path.to.my.server'+/ date , // should format date her
timeout: 6000
}).then(function (success) {
date = success.date[0].date; //0 is always the newest message
//Do some stuff with the data; all the datas will be available in $scope.allDatas
$scope.allDatas = $scope.allDatas.concat(success.data);
// call again ?
if( /* decide when you stop getting data */ ){
getData(date);
}
}, function (error) {
console.error("Could not retrieve new messages: \n", error.data);
errcallback(error);
});
}
var date = new Date();
// launch the function
getData(date);
}
I'm attempting to implement an asynchronous computed observable as show here.
I can do it successfully for one ajax call. The challenge I have at the moment is how to perform various ajax calls in a loop building an array asynchronously and then returning the array to my computed observable array using jQuery promises.
Basically the HTML form works in the following way:
This a student course form.
For each row, users type the person number and on another column they'll type a list of course ids separated by commas. Eg 100, 200, 300.
The purpose of the computed observable is to store an array
containing course details for the courses entered in step 2.
The details are obtained by firing ajax calls for each course and storing HTTP response in the array.
I don't want users to wait for the result, thus the reason to implement an async computed observable.
My problem: I'm having problem returning the value of the final array to the observable. It's always undefined. The ajax calls work fine but perhaps I'm still not handling the promises correctly.
Here's the code for my class:
function asyncComputed(evaluator, owner) {
var result = ko.observable(), currentDeferred;
result.inProgress = ko.observable(false); // Track whether we're waiting for a result
ko.computed(function () {
// Abort any in-flight evaluation to ensure we only notify with the latest value
if (currentDeferred) { currentDeferred.reject(); }
var evaluatorResult = evaluator.call(owner);
// Cope with both asynchronous and synchronous values
if (evaluatorResult && (typeof evaluatorResult.done == "function")) { // Async
result.inProgress(true);
currentDeferred = $.Deferred().done(function (data) {
result.inProgress(false);
result(data);
});
evaluatorResult.done(currentDeferred.resolve);
} else // Sync
result(evaluatorResult);
});
return result;
}
function personDetails(id, personNumber, courseIds) {
var self = this;
self.id = ko.observable(id);
self.personNumber = ko.observable(personNumber);
self.courseIds = ko.observable(courseIds);
// Computed property to extract PIC details for additional PICs.
// This is computed observable which returns response asynchronously
self.courseDetails = asyncComputed(function () {
var courseIdsArray = self.courseIds().split(",");
var arr = [];
var arr_promises = [];
function getCourseDetails(courseId) {
var dfrd = $.Deferred();
var content = {};
content.searchString = courseId;
var url = 'MyURL';
return $.ajax(url, {
type: 'POST',
dataType: 'json',
data: requestData, // content of requestData is irrelevant. The ajax call works fine.
processdata: true,
cache: false,
async: true,
contentType: "application/json"
}).done(function (data) {
arr.push(new PicDetails(data.GenericIdentifierSearchResult[0]));
}).fail(function () {
alert("Could not retrieve PIC details");
}).then(function () {
dfrd.resolve();
});
}
if (courseIdsArray.length > 0) {
$.each(courseIdsArray, function (index, courseId) {
if (courseId.length > 0) {
arr_promises.push(getCourseDetails(courseId));
}
});
};
$.when.apply($, arr_promises).done(function () {
return arr;
})
}, this);
}
I think you dont really need a separate api/code for this.
You could just create observables for every input/value that changes on your site, and create a computed observable based on those.
e.g in rough pseudo code
self.id = ko.observable(id);
self.personNumber = ko.observable(personNumber);
self.courseIds = ko.observable(courseIds);
self.courseDetailsArray = ko.observableArray([]);
self.courseDetails = ko.computed(function() {
//computed the course details based on other observables
//whenever user types in more course ids, start loading them
$.get( yoururl, {self.courseIds and self.id}).success(data) {
when finished async loading, parse the data and push the new course details into final array
self.courseDetailsArray.push( your loaded and parsed data );
//since courseDetailsArray is observableArray, you can have further computed observables using and re-formatting it.
}
});
I have something a bit different from your approach, but you can build something like an asyncComputed out of it if you prefer:
make a simple observable that will hold the result
make a dictionary of promises that you'll basically keep in sync with the array of course ids
when the array of course ids change, add / remove from the dictionary of promises
wrap all your promises in a when (like you're doing) and set the result when they're all done
Basic idea:
var results = ko.observable([]);
var loadingPromises = {};
var watcher = ko.computed(function () {
var ids = ko.unwrap(listOfIds);
if (ids && ids.length) {
ids.forEach(function (id) {
if (!loadingPromises.hasOwnProperty(id)) {
loadingPromises[id] = $.get(url, {...id...});
}
});
var stillApplicablePromises = {};
var promises = []; // we could delete from loadingPromises but v8 optimizes delete poorly
Object.getOwnPropertyNames(loadingPromises).forEach(function (id) {
if (ids.indexOf(id) >= 0) {
stillApplicablePromises[id] = loadingPromises[id];
promises.push(loadingPromises[id]);
}
});
loadingPromises = stillApplicablePromises;
$.when.apply(this, promises).then(function () {
// process arguments here however you like, they're the responses to your promises
results(arguments);
});
} else {
loadingPromises = {};
results([]);
}
}, this);
This is the file (that may change) where you can see this "in real life": https://github.com/wikimedia/analytics-dashiki/blob/master/src/components/wikimetrics-visualizer/wikimetrics-visualizer.js
And the basic fiddle: http://jsfiddle.net/xtsekb20/1/
I have an issue with a method ive created for an object ive created. one of the methods requires a callback to another method. the problem is i cant add the data to the object that called the method. it keeps coming back as undefined. otherwise when i send the data to the console it is correct. how can i get the data back to the method?
var blogObject = new Object();
var following = [...];
//get posts from those blogs
blogObject.getPosts = function () {
var followersBlogArray = new Array();
for (var i = 0; i < this.following.length;i++){
var followersBlog = new Object();
// get construct blog url
var complete_blog_url = ...;
i call the getAvatar function here sending the current user on the following array with it.
followersBlog.avatar = blogObject.getAvatar(this.following[i]);
that part goes smoothly
followersBlogArray.push(followersBlog);
}
this.followersBlogArray = followersBlogArray;
}
here is the function that gets called with the current user in following array
this function calls an ajax function
blogObject.getAvatar = function (data) {
console.log("get avatar");
var url = "..."
this ajax function does its work and has a callback function of showAvatar
$(function() {
$.ajax({
type: "GET",
dataType: "jsonp",
cache: false,
url: url,
data: {
jsonp:"blogObject.showAvatar"
}
});
});
}
this function gets called no problem when getAvatar is called. i cant however get it to add the data to the followersBlog object.
blogObject.showAvatar = function (avatar) {
return avatar
}
everything in here works fine but i cant get the showAvatar function to add to my followersBlog object. ive tried
blogObject.showAvatar = function (avatar) {
this.followersBlog.avatar = avatar;
return avatar
}
that didnt work of course. it shows up as undefined. can anyone help?
so somethings like...
$(function() {
$.ajax({
type: "GET",
dataType: "jsonp",
cache: false,
url: url,
complete: function () {
this.avatar = data;
}
data: {
jsonp:"blogObject.showAvatar"
}
});
});
}
Welcome to the world of asynchronous programming.
You need to account for the fact that $.ajax() will not return a value immediately, and Javascript engines will not wait for it to complete before moving on to the next line of code.
To fix this, you'll need to refactor your code and provide a callback for your AJAX call, which will call the code that you want to execute upon receiving a response from $.ajax(). This callback should be passed in as the complete argument for $.ajax().
The correct option for setting the JSONP callback is jsonpCallback. The recommendation from the API for .ajax(...) is to set it as a function.
{
// ...
jsonpCallback: function (returnedData) {
blogObject.showAvatar(returnedData);
},
// ...
}
I have a the following java script object
function eventTypeObj() {
allEventTypes = [];
// When the object is created go and get all the event types that can be included in journey or clusters.
$.ajax({
url: "/ATOMWebService.svc/GetDisplayEventTypes",
dataType: "json",
success: function(result) {
allEventTypes = eval("(" + result.d + ")");
}
});
// Returns a list of all the event type IDS.
this.getEventTypeIds = function() {
var eventTypeIDs = [];
for (var i = 0; i < allEventTypes.length; i++) {
eventTypeIDs.push(allEventTypes[i].Id);
}
return eventTypeIDs;
};
}
I was wondering if there is a way stop some one calling the eventTypeObj.getEventTypeIds(); before the ajax call in the constructor has succeeded, and there is no data in the allEventTypes array?
Something like this would be way better (im not guaranteeing this is 100% working, but the concept is sound):
function eventTypeObj() {
this.allEventTypes = [];
this.hasLoadedEventTypes = false;
var loadEventTypes = function(cb) {
$.ajax({
url: "/ATOMWebService.svc/GetDisplayEventTypes",
dataType: "json",
success: function(result) {
this.allEventTypes = eval("(" + result.d + ")");
this.hasLoadedEventTypes = true;
cb();
}
});
};
this.getEventTypeIds = function(updateEventTypes, callback) {
var _getEventTypeIds = function() {
var eventTypeIDs = [];
for (var i = 0; i < this.allEventTypes.length; i++) {
eventTypeIDs.push(this.allEventTypes[i].Id);
}
return eventTypeIDs;
};
if (!this.hasLoadedEventTypes || updateEventTypes) {
loadEventTypes(function(){ callback(_getEventTypeIds()); });
}
else callback(_getEventTypeIds());
};
}
Example usage:
var eto = new eventTypeObj();
eto.getEventTypeIds(false, function(eventTypeIdArray) {
// do stuff with the id array
});
/*
somewhere later on you want to get an updated eventTypeId array
in case the event types have changed.
*/
eto.getEventTypeIds(true, function(eventTypeIdArray) {
// do stuff with the updated ids
});
var allowCall = false;
function eventTypeObj() {
allEventTypes = [];
// When the object is created go and get all the event types that can be included in journey or clusters.
$.ajax({
url: "/ATOMWebService.svc/GetDisplayEventTypes",
dataType: "json",
success: function(result) {
allEventTypes = eval("(" + result.d + ")");
allowCall = true;
}
});
// Returns a list of all the event type IDS.
this.getEventTypeIds = function() {
if(!allowCall) return; // or pop up a message
var eventTypeIDs = [];
for (var i = 0; i < allEventTypes.length; i++) {
eventTypeIDs.push(allEventTypes[i].Id);
}
return eventTypeIDs;
};
}
Or just check if allEventTypes is empty or not.
There is no way to prevent someone from calling it too soon. What would you want to have happen if they call it too soon?
It looks like your code now currently returns an empty array if allEventTypes hasn't yet been filled in. You can decide whether the empty array is the right result or if you should throw an exception when it's called too early to make it absolutely clear to the caller that the data is not yet available.
You could provide some helper code for people who need that information, but it might not yet be available. For example, you could allow them to register a callback that would get called from the success handler after the data had been filled in. You could allow them to query whether the data is available yet.
If you don't want the responsibility for the timing to be on the callers, then you cannot offer a synchronous way to get this information. Instead, you would only offer a callback mechanism for getting the data. If the data is ready, the callback would get called immediately. If the data is not ready, the callback would get called when the ajax function completes. In either case, the caller would have to process the data in the callback only and getEventTypeIds would not be a normal call to get the data like it is now, but rather a call to register a callback that would be called with the data when was ready. This would relieve the caller from having to know implementation details of when the data was ready, but would force them to use the asynchronous nature of the callback mechanism.
this.getEventTypeIds = function(callback) {
if (allEventTypes.length > 0) {
// data is ready call the callback with the data now
} else {
// store the callback to be called later from the success handler
}
}
You can check if the eventType array is empty, right?
if(allEventTypes.length == 0)
{
return;
}