Accessing Data from JavaScript Object's Array Member Variable - javascript

I'm writing a jQuery plugin for work which pulls in RSS feed data using Google's Feed API. Using this API, I'm saving all of the relevant RSS feed data into an object, then manipulating it through methods. I have a function which is supposed to render the RSS feed onto the webpage. Unfortunately, when I try to display the individual RSS feed entries, I get an error. Here's my relevant code:
var RSSFeed = function(feedTitle, feedUrl, options) {
/*
* An object to encapsulate a Google Feed API request.
*/
// Variables
this.description = "";
this.entries = [];
this.feedUrl = feedUrl;
this.link = "";
this.title = feedTitle;
this.options = $.extend({
ssl : true,
limit : 4,
key : null,
feedTemplate : '<article class="rss-feed"><h2>{title}</h1><ul>{entries}</ul></article>',
entryTemplate : '<li><h3>{title}</h3><p>by: {author} # {publishedDate}</p><p>{contentSnippet}</p></li>',
outputMode : "json"
}, options || {});
this.sendFeedRequest = function() {
/*
* Makes the AJAX call to the provided requestUrl
*/
var self = this;
$.getJSON(this.encodeRequest(), function(data) {
// Save the data in a temporary object
var responseDataFeed = data.responseData.feed;
// Now load the data into the RSSFeed object
self.description = responseDataFeed.description;
self.link = responseDataFeed.link;
self.entries = responseDataFeed.entries;
});
};
this.display = function(jQuerySelector) {
/*
* Displays the RSSFeed onto the webpage
* Each RSSEntry will be displayed wrapped in the RSSFeed's template HTML
* The template markup can be specified in the options
*/
var self = this;
console.log(self);
console.log(self.entries);
};
};
$.rssObj = function(newTitle, newUrl, options) {
return new RSSFeed(newTitle, newUrl, options);
};
// Code to call the jquery plugin, would normally be found in an index.html file
rss = $.rssObj("Gizmodo", "http://feeds.gawker.com/Gizmodo/full");
rss.sendFeedRequest();
rss.display($('div#feed'));
Obviously, my display() function isn't complete yet, but it serves as a good example. The first console.log() will write all of the relevant data to the console, including the entries array. However, when I try to log the entries array by itself, it's returning an empty array. Any idea why that is?

I guess the problem is that display() is called without waiting for the AJAX request to complete. So the request is still running while you already try to access entries - hence the empty array.
In order to solve this you could move the call to display() into the callback of $.getJSON(). You just have to add the required selector as a parameter:
this.sendFeedRequest = function(selector) {
var self = this;
$.getJSON(this.encodeRequest(), function(data) {
var responseDataFeed = data.responseData.feed;
...
self.entries = responseDataFeed.entries;
self.display(selector);
});
};
EDIT:
If you don't want to move display() into the callback, you could try something like this (untested!):
var RSSFeed = function(feedTitle, feedUrl, options) {
...
this.loading = false;
this.selector = null;
this.sendFeedRequest = function() {
var self = this;
self.loading = true;
$.getJSON(this.encodeRequest(), function(data) {
...
self.loading = false;
if (self.selector != null) {
self.display(self.selector);
}
});
};
this.display = function(jQuerySelector) {
var self = this;
if (self.loading) {
self.selector = jQuerySelector;
}
else {
...
}
};
};

Related

How to preload JSON link?

I've got a function that needs to call a link (JSON format), the fact is that I would like to be able to preload this link to smooth and reduce the operation time when calling the function.
onSelectionChanged: function (selectedItems) {
selectedItems.selectedRowsData.forEach(function(data) {
if(data) {
colorMe(data.target)
}
});
}
function colorMe(item){
globalItem = item;
request('http://blablabla/?format=json',findMaterial);
};
function findMaterial(data){
jq310.each(data, function(table) {
if (data[table].identifier == globalItem){
globalData = data[table]
request('http://another-blablabla/?format=json',findMatchArea);
};
});
};
function findMatchArea(areas){
jq310.each(areas, function(area) {
blablabla
The request function that I built just look if the link as been already called, so it's reloading it if true. And also send data from the link to the called function.
If you'r looking to load a static json file you should concider loading it on the top of your file. To do so you should store the datas in a global variable like that :
let datas;
request('http://blablabla/?format=json', (data) => {
datas = data
});
onSelectionChanged: function (selectedItems) {
selectedItems.selectedRowsData.forEach(function(data) {
if(data) {
globalItem = data.target;
findMaterial();
}
});
}
function colorMe(item){
globalItem = item;
};
function findMaterial(){
const data = datas;
jq310.each(data, function(table) {
if (data[table].identifier == globalItem){
globalData = data[table]
request('http://another-blablabla/?format=json',findMatchArea);
};
});
};
I finally found a way to do it properly, here it is :
var mylink = 'https://fr.wikipedia.org/wiki/JavaScript';
function preloadURL(link){
var xhReq = new XMLHttpRequest();
xhReq.open("GET", link, false);
xhReq.send(null);
var jsonObject = JSON.parse(xhReq.responseText);
return jsonObject;
};
jsonObjectInv = preloadURL(mylink);
And I just point to my json variable to parse it (really faster)
function colorMe(item){
globalItem = item;
findMaterial(jsonObjectInv);
};
Problem solved

Set Value from JSON via AJAX

I'm using Github Gists for a web playground I'm making as a side project. I load two json files into the editor. 1 handles all the libraries (jquery, bootstrap, etc:) and another for the users settings (fontsize, version, etc:)
So anyway I have this JSON named settings
var settings = gistdata.data.files["settings.json"].content
var jsonSets = JSON.parse(settings)
I parse and attempted to grab an object from the JSON and set it as a value of a input textbox.
Now console.log(jsonSets.siteTitle) works perfectly fine
but when I try to change the input dynamically...
$("[data-action=sitetitle]").val(jsonSets.siteTitle).trigger("change")
The problem is it's not actually applying the value!
The only way I've been able to successfully apply the value is...
setTimeout(function() {
$("[data-action=sitetitle]").val(jsonSets.siteTitle).trigger("change")
}, 5000)
Which is ridiculously slow.
Does anyone know why it's not applying the value?
in addition.
How can I solve this problem?
var hash = window.location.hash.substring(1)
if (window.location.hash) {
function loadgist(gistid) {
$.ajax({
url: "https://api.github.com/gists/" + gistid,
type: "GET",
dataType: "jsonp"
}).success(function(gistdata) {
var libraries = gistdata.data.files["libraries.json"].content
var settings = gistdata.data.files["settings.json"].content
var jsonLibs = JSON.parse(libraries)
var jsonSets = JSON.parse(settings)
// Return libraries from json
$.each(jsonLibs, function(name, value) {
$(".ldd-submenu #" + name).prop("checked", value)
})
// Return font settings from json
var siteTitle = jsonSets.siteTitle
var WeaveVersion = jsonSets.version
var editorFontSize = jsonSets.editorFontSize
var WeaveDesc = jsonSets.description
var WeaveAuthor = jsonSets.author
$("[data-action=sitetitle]").val(siteTitle).trigger("change")
$("[data-value=version]").val(WeaveVersion).trigger("change")
$("[data-editor=fontSize]").val(editorFontSize).trigger("change")
$("[data-action=sitedesc]").val(WeaveDesc).trigger("change")
$("[data-action=siteauthor]").val(WeaveAuthor).trigger("change")
}).error(function(e) {
// ajax error
console.warn("Error: Could not load weave!", e)
})
}
loadgist(hash)
} else {
// No hash found
}
My problem was actually related to localStorage.
I cleared it localStorage.clear(); ran the ajax function after and it solved the problem.
var hash = window.location.hash.substring(1)
if (window.location.hash) {
localStorage.clear()
function loadgist(gistid) {
$.ajax({
url: "https://api.github.com/gists/" + gistid,
type: "GET",
dataType: "jsonp",
jsonp: "callback"
}).success(function(gistdata) {
var htmlVal = gistdata.data.files["index.html"].content
var cssVal = gistdata.data.files["index.css"].content
var jsVal = gistdata.data.files["index.js"].content
var mdVal = gistdata.data.files["README.md"].content
var settings = gistdata.data.files["settings.json"].content
var libraries = gistdata.data.files["libraries.json"].content
var jsonSets = JSON.parse(settings)
var jsonLibs = JSON.parse(libraries)
// Return font settings from json
var siteTitle = jsonSets.siteTitle
var WeaveVersion = jsonSets.version
var editorFontSize = jsonSets.editorFontSize
var WeaveDesc = jsonSets.description
var WeaveAuthor = jsonSets.author
$("[data-action=sitetitle]").val(siteTitle)
$("[data-value=version]").val(WeaveVersion)
$("[data-editor=fontSize]").val(editorFontSize)
$("[data-action=sitedesc]").val(WeaveDesc)
$("[data-action=siteauthor]").val(WeaveAuthor)
storeValues()
// Return settings from the json
$(".metaboxes input.heading").trigger("keyup")
// Return libraries from json
$.each(jsonLibs, function(name, value) {
$(".ldd-submenu #" + name).prop("checked", value).trigger("keyup")
})
// Set checked libraries into preview
$("#jquery").trigger("keyup")
// Return the editor's values
mdEditor.setValue(mdVal)
htmlEditor.setValue(htmlVal)
cssEditor.setValue(cssVal)
jsEditor.setValue(jsVal)
}).error(function(e) {
// ajax error
console.warn("Error: Could not load weave!", e)
})
}
loadgist(hash)
} else {
// No hash found
}

Return string from second function

Well i have created a function to return the picture url. See code below:
function loadAttachment(itemid) {
web = context.get_web();
attachmentFolder = web.getFolderByServerRelativeUrl("Lists/LijstMedewerkers/Attachments/" + itemid);
attachmentFiles = attachmentFolder.get_files();
//Load attachments
context.load(attachmentFiles);
context.executeQueryAsync(onLoaddAttachmentSuccess, onLoadAttachmentFail);
alert(picture);
return picture;
}
function onLoadAttachmentFail(sender, args) {
alert('Failed to get lists items. Error:' + args.get_message());
}
function onLoaddAttachmentSuccess(sender, args) {
// Enumerate and list the Asset Attachments if they exist
var attachementEnumerator = attachmentFiles.getEnumerator();
while (attachementEnumerator.moveNext()) {
var attachment = attachementEnumerator.get_current();
picture = attachment.get_serverRelativeUrl();
}
}
Well it's not returning the value of the picture. When i do an alert i see the value but with the return it's not working. even if i put the picture in the itemid.
Any idea what i'm doing wrong ?
Since SP.ClientContext.executeQueryAsync method is async:
SP.ClientContext.executeQueryAsync(succeededCallback, failedCallback)
succeededCallback is used for declaring function that contains the returned results.
When working with asynchronous API such as JSOM the following patterns are commonly used:
Using nested callbacks
Using the promises pattern
The below example demonstrates how to retrieve attachment files using callback approach:
function loadAttachments(listTitle, itemId,success,error) {
var context = new SP.ClientContext.get_current();
var web = context.get_web();
var list = web.get_lists().getByTitle(listTitle);
var listItem = list.getItemById(itemId);
var files = listItem.get_attachmentFiles();
context.load(files);
context.executeQueryAsync(function(){
success(files);
},
error);
}
Usage
Get first file attachment url
loadAttachments('Projects',3,
function(attachmentFiles){
if(attachmentFiles.get_count() > 0) {
var attachmentFile = attachmentFiles.getItemAtIndex(0);
var fileUrl = attachmentFile.get_serverRelativeUrl();
//...
}
},
function(sender,args){
console.log(args.get_message());
});

Can't access properties of my Javascript object

I'm using Angular.js to fetch a single record from my API. I'm getting the record back as an object, I can log the object and see it's properties but I cannot access any of the properties. I just get undefined.
var template = Template.get({id: id});
$scope.template = template;
...
console.log(template); // displays object
console.log(template.content); // undefined
UPDATE
var id = $routeParams.templateId;
var template = Template.get({id: id});
$scope.template = template;
/*** Template placeholders ***/
$scope.updatePlaceholders = function () {
var placeholders = [];
var content = template.content;
console.log(template); // dumps the object in the screenshot
console.log("content" in template); // displays false
// get placeholders that match patter
var match = content.match(/{([A-z0-9]+)}/gmi);
...
}
$scope.$on('$viewContentLoaded', function(){
$scope.updatePlaceholders();
});
You need to wait for your HTTP request to complete, then specify what to do in the callback. In this case I've taken it a step further and added a listener to your template object so there's no callback dependency between updatePlaceholders and your resource.
var id = $routeParams.templateId;
var template = Template.get({id: id}, function(res) {
$scope.template = template;
});
/*** Template placeholders ***/
$scope.updatePlaceholders = function () {
var placeholders = [];
var content = $scope.template.content;
console.log($scope.template);
console.log("content" in $scope.template);
// get placeholders that match patter
var match = content.match(/{([A-z0-9]+)}/gmi);
...
}
$scope.$watch('template', function(newValue){
if(newValue) $scope.updatePlaceholders();
});

Uncaught TypeError: Object has no method ... Javascript

I'm having an issue where I get an error that says...
"Uncaught TypeError: Object f771b328ab06 has no method 'addLocation'"
I'm really not sure what's causing this. The 'f771b328ab06' is a user ID in the error. I can add a new user and prevent users from being duplicated, but when I try to add their location to the list, I get this error.
Does anybody see what's going wrong? The error occurs in the else statement of the initialize function as well (if the user ID exists, just append the location and do not create a new user). I have some notes in the code, and I'm pretty sure that this is partly due to how I have modified an example provided by another user.
function User(id) {
this.id = id;
this.locations = [];
this.getId = function() {
return this.id;
};
this.addLocation = function(latitude, longitude) {
this.locations[this.locations.length] = new google.maps.LatLng(latitude, longitude);
alert("User ID:" );
};
this.lastLocation = function() {
return this.locations[this.locations.length - 1];
};
this.removeLastLocation = function() {
return this.locations.pop();
};
}
function Users() {
this.users = {};
//this.generateId = function() { //I have omitted this section since I send
//return Math.random(); //an ID from the Android app. This is part of
//}; //the problem.
this.createUser = function(id) {
this.users[id] = new User(id);
return this.users[id];
};
this.getUser = function(id) {
return this.users[id];
};
this.removeUser = function(id) {
var user = this.getUser(id);
delete this.users[id];
return user;
};
}
var users = new Users();
function initialize() {
alert("Start");
$.ajax({
url: 'api.php',
dataType: 'json',
success: function(data){
var user_id = data[0];
var latitude = data[1];
var longitude = data[2];
if (typeof users.users[user_id] === 'undefined') {
users.createUser(user_id);
users.users[user_id] = "1";
user_id.addLocation(latitude, longitude); // this is where the error occurs
}
else {
user_id.addLocation(latitude, longitude); //here too
alert(latitude);
}
}
})
}
setInterval(initialize, 1000);
Since I get the ID from the phone and do not need to generate it here (only receive it), I commented out the part that creates the random ID. In doing this, I had to add a parameter to the createUser method within Users() so that I can pass the ID as an argument from Initialize(). See the changes to createUser below:
Before, with the generated ID (the part where the number is generated is in the above code block with comments):
this.createUser = function() {
var id = this.generateId();
this.users[id] = new User(id);
return this.users[id];
};
After, with the ID passed as an argument:
this.createUser = function(id) {
this.users[id] = new User(id);
return this.users[id];
};
If anyone has any suggestions I would really appreciate it. Thanks!
Here you're getting user_id by :
var user_id = data[0];
So it's a part of the json answer : maybe a string or another dictionnary, this can't be a user object. You should try to update your code in your success function inside the "if" block by :
user = users.createUser(user_id);
//The following line is a non sense for me you put an int inside
//an internal structure of your class that should contain object
//users.users[user_id] = "1";
user.addLocation(latitude, longitude);

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