We Keep Coding

How to access and use multiple data from json object? Do I need to make an array?

I am a beginner and using $.get to retrieve data from a rest API such as:
[{"id":"1","url":"http:\/\/123.456.78.910\/workforce\/images\/item1.jpg","price":"99","description":"Mobile Phone"},
{"id":"2","url":"http:\/\/123.456.78.910\/workforce\/images\/item2.jpg","price":"98","description":"Laptop"}
{"id":"3","url":"http:\/\/123.456.78.910\/workforce\/images\/item3.jpg","price":"92","description":"Console"}] }
$.get('http://xxxxxxxxxxx,
function (data) {
var obj = $.parseJSON(data);
So from what I understand I have retrieved the data from the REST API and parsed it so it is stored in a variable called obj.
My question is, how do I access and use each unique record in the obj variable?
Each record has it's own picture (item1.jpg, item2.jpg etc).
Whem my app loads I want it to show the item1.jpg image, and I want to be able to navigate to the other item pictures using buttons (previous / next).
I also want the description and price to be displayed underneath in some text input fields.
What I have figured so far is that I should:
Iterate through the obj variable, and store each record into an array.
Upon app initialisation I can set the default value for the image placeholder to array[index0].url, and set the description and price fields.
I can then set the previous and next buttons to array[currentIndex-1] or array[currentIndex+1].
Would this be the best way to do it?
Or can I just do this without using an array and manipulate the obj.data directly?
Thanks!!!

I may not be understanding what exactly what you want to do but I think I have the gist. If you just want to show the picture then the array of just images probably wouldn't be a bad idea. However, it looks like the Jason you're getting is already in an array. You can just use array index notation to get to what you want.
ie)
var arr = //your json response ;
var current = 0; //sets currently displayed object to the first in the array
var setCurrent = function () {
var image = arr[current]["url"];
}
You can then modify current however you want (on click on arrow iterate up/down, etc) then call the setCurrent function to set your image the the one you want. Hope that helps!

You can use the response you have from $.get() directly.
It is an array of objects.
You can use it like this:
console.log(data[2].description);
// outputs: "Console"
I've made a CodePen demo where it has a 4th object with a real image url to show you how to use the url info...
EDIT
Just in case you wouldn't know this:
You can use the response inside the scope of the $.get() callback...
You can not use it straith after the $.get() outside the callback since $.get() is asynchronous.
You can use it in some other handler wich will happen after the response is received.
var getResponse;
$.get('http://xxxxxxxxxxx', function (data) {
getResponse = data;
console.log(data[2].description);
// outputs: "Console"
console.log(getResponse[2].description);
// outputs: "Console"
});
console.log(getResponse[2].description);
// outputs: "Undefined"
// But since this handler will be triggered long after the response is obtained:
$("#somebutton").click(function(){
console.log(getResponse[2].description);
// outputs: "console"
});

In order for your page javascript to be able to access the data retrieved from your ajax request, you'll need to assign it to some variable which exists outside the callback function.
You will need to wait until the ajax request has been processed before you can read the array. So you might want to set the actual default image to be something that doesn't rely on the ajax request (a local image).
Here's a simple approach
// fake testing ajax func
function fakeget (url, callback) {
setTimeout(callback(JSON.stringify([
{"id":"1","url":"http:\/\/123.456.78.910\/workforce\/images\/item1.jpg","price":"99","description":"Mobile Phone"}, {"id":"2","url":"http:\/\/123.456.78.910\/workforce\/images\/item2.jpg","price":"98","description":"Laptop"},
{"id":"3","url":"http:\/\/123.456.78.910\/workforce\/images\/item3.jpg","price":"92","description":"Console"}
])), 1000);
}
// real code starts here
// global variables for ajax callback and setImg func to update
var imageData, currentImg;
// change this back to $.get for real
fakeget('http://xxxxxxxxxxx',
function (data) {
imageData = $.parseJSON(data);
setImg(0);
}
);
function setImg(index) {
// turns negative indices into expected "wraparound" index
currentImg = (index % imageData.length + imageData.length) % imageData.length;
var r = imageData[currentImg];
$("#theImg").attr('src', r.url);
$('#theDescription').text(r.price + " " + r.description);
}
$("#prev").click(function () {
setImg(currentImg - 1);
});
$("#next").click(function () {
setImg(currentImg + 1);
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div>
<img id='theImg' src='somedefault.jpg'>
<div id='theDescription'></div>
</div>
<button id='prev'>Prev</button>
<button id='next'>Next</button>

Few observations :
Your JSON Object is not a valid JSON.
No need to parse it again your data is already a JSON Object.
Working fiddle
var data = [{"id":"1","url":"http:\/\/123.456.78.910\/workforce\/images\/item1.jpg","price":"99","description":"Mobile Phone"},{"id":"2","url":"http:\/\/123.456.78.910\/workforce\/images\/item2.jpg","price":"98","description":"Laptop"}, {"id":"3","url":"http:\/\/123.456.78.910\/workforce\/images\/item3.jpg","price":"92","description":"Console"}];
for (var i in data) {
var imgUrl = data[i].url;
console.log(imgUrl);
}

Two-way data binding for a Meteor app

I've built an app that is form-based. I want to enable users to partially fill out a form, and then come back to it at a later date if they can't finish it at the present. I've used iron router to create a unique URL for each form instance, so they can come back to the link. My problem is that Meteor doesn't automatically save the values in the inputs, and the form comes up blank when it is revisited/refreshes. I tried the below solution to store the data in a temporary document in a separate Mongo collection called "NewScreen", and then reference that document every time the template is (re)rendered to auto fill the form. However, I keep getting an error that the element I'm trying to reference is "undefined". The weird thing is that sometimes it works, sometimes it doesn't. I've tried setting a recursive setTimeout function, but on the times it fails, that doesn't work either. Any insight would be greatly appreciated. Or, if I'm going about this all wrong, feel free to suggest a different approach:
Screens = new Meteor.Collection('screens') //where data will ultimately be stored
Forms = new Meteor.Collection('forms') //Meteor pulls form questions from here
NewScreen = new Meteor.Collection('newscreen') //temporary storage collection
Roles = new Meteor.Collection('roles'); //displays list of metadata about screens in a dashboard
//dynamic routing for unique instance of blank form
Router.route('/forms/:_id', {
name: 'BlankForm',
data: function(){
return NewScreen.findOne({_id: this.params._id});
}
});
//onRendered function to pull data from NewScreen collection (this is where I get the error)
Template.BlankForm.onRendered(function(){
var new_screen = NewScreen.findOne({_id: window.location.href.split('/')[window.location.href.split('/').length-1]})
function do_work(){
if(typeof new_screen === 'undefined'){
console.log('waiting...');
Meteor.setTimeout(do_work, 100);
}else{
$('input')[0].value = new_screen.first;
for(i=0;i<new_screen.answers.length;i++){
$('textarea')[i].value = new_screen.answers[i];
}
}
}
do_work();
});
//onChange event that updates the NewScreen document when user updates value of input in the form
'change [id="on-change"]': function(e, tmpl){
var screen_data = [];
var name = $('input')[0].value;
for(i=0; i<$('textarea').length;i++){
screen_data.push($('textarea')[i].value);
}
Session.set("updateNewScreen", this._id);
NewScreen.update(
Session.get("updateNewScreen"),
{$set:
{
answers: screen_data,
first: name
}
});
console.log(screen_data);
}

If you get undefined that could mean findOne() did not find the newscreen with the Id that was passed in from the url. To investigate this, add an extra line like console.log(window.location.href.split('/')[window.location.href.split('/').length-1], JSON.stringify(new_screen));
This will give you both the Id from the url and the new_screen that was found.
I would recommend using Router.current().location.get().path instead of window.location.href since you use IR.
And if you're looking for two way binding in the client, have a look at Viewmodel for Meteor.

Query entire class vs first object in the class

In my cloud code I want to retrieve the first object in the "Messages" class. Then i want to grab some information from that object, send it to another class, and finally delete that object from the "Messages" class i originally pulled it from.
My question is do i need to query the entire "Messages" class just to get the first object in it? I don't want to slow down my app due to inefficient code.
Parse.Cloud.afterSave("sendMessage", function(Parse.Message, response) {
var body = null;
var senderName = null;
var senderId = null;
var randUsers = [];
var query = new.Parse.Query(Parse.Message);
query.find({
success: function(results){
body.push(results[1].get("messageBody"));
senderName.push(results[1].get("senderName"));
senderId.push(results[1].get("senderId"));
response.success(getUsers);
},
error: funtion(error){
response.error("Error");
}
});
});
to avoid confusion: "getUsers" is an arbitrary function call.

To retrieve entry from class, you need the query the table. However, your problem is getting the first record which does not require getting the all record. From your code I can see that you get the first record of result array (result[1] ). You can apply the solution; getting the first record of the class that you want to query. You can do it via two ways; either you can set the limit 1 to your query or you can use the first() method. The Parse.Query JS API link is below;
https://parse.com/docs/js/symbols/Parse.Query.html
Check the limit and first methods.
Hope this helps.
Regards.

How do I store multiple options for a Chrome extension?

I am working on a Chrome extension that replaces words on websites with different words.
I allow users to input their own words that they would like to be replaced, and I save these like this:
function storeOptions(){
var words = new Object(); // storageArea.set() method takes an object that contains all the items to be stored. This Object contains those.
$("option").each(function(key,value){ // .each(index, element)
words[value.id] = value.text;
chrome.storage.sync.set(words, function(){console.log("Stored: "+value.text);});
});
}
Before this was implemented I was successfully enabling and disabling the extension with a browseraction that used a setting stored in the same storagearea in a similar way:
chrome.storage.sync.set({"status":"enabled"});
The problem I am facing is that after implementing the option to add words, the status either isn't being stored properly or is affected by the options, as when I try to retrieve it it doesn't have the values "enabled" or "disabled" as shown here:
chrome.storage.sync.get("status", function(result) {
console.log("status: "+result["status"]); // status: status
});
I was thinking that perhaps I could store the words to replace as an array called in a way like:
chrome.storage.sync.set({"words" : words});
And I would then be able to differentiate the two by getting "status" or "words", but that did not work.
How can I store status and the words without them interfering with each other?

The only reason for what you describe to happen is if there is an <option> element with id status and value status (in which case it would overwrite the original status).
In any case, it is (as you suggested) a good idea to "encapsulate" all option-related key-value pairs in an object (not necessarily an array) inside storage.
(Finally, there is no need to store the values one-by-one. It would be more efficient to first create the whole object and then store it with a single call to chrome.storage.sync.set().)
function storeOptions() {
const words = {};
$('option').each((idx, element) => words[element.id] = element.text);
chrome.storage.sync.set({words: words});
}
Now your storage.sync will be looking like this:
{
"status": "enabled",
"words": {
"option_id1": "option_text1",
"option_id2": "option_text2",
...
}
}
You can retrieve the values like this:
// Retrieve the extension status:
chrome.storage.sync.get('status', items => {
const status = items.status;
...
});
// Retrieve the words:
chrome.storage.sync.get('words', items => {
const words = items.words;
Object.keys(words).forEach(key => {
console.log(`Replacing '${key}' with '${words[key]}'...`);
...
});
});

how to serialize a form without jQuery? [duplicate]

This question already has answers here:
form serialize javascript (no framework)
(25 answers)
Closed 8 years ago.
For a lot of reasons (first of all: learning javascript), I need to serialize a form without jQuery, and send the resulting serialized data-structure to a php page with ajax.
The serialized data must be in JSON format.
How can I do that?
--EDIT--
this is how my form looks like: http://jsfiddle.net/XGD4X/

I am working on a similar problem, and I agree that it is worthwhile to learn how to program first without using a framework. I am using a data object (BP.reading) to hold the information, in my case a blood pressure reading. Then the JSON.stringify(dataObj) dose the work for you.
Here is the handler for the 'save' button click, which is a method on the dataObj. Note I am using a form instead of a table to input data, but the same idea should apply.
update: function () {
var arr = document.getElementById("BP_input_form").firstChild.elements,
request = JDK.makeAjaxPost(); // simple cross-browser httpxmlrequest with post headings preset
// gather the data and store in this data obj
this.name = arr[0].value.trim();
...
this.systolic = arr[3].value;
this.diastolic = arr[4].value;
// still testing so just put server message on page
request.callback = function (text) {
msgDiv.innerHTML += 'server said ' + text;
};
//
request.call("BP_update_server.php", JSON.stringify(this));
}
I hope this is helpful
* edit to show generic version *
In my program, I am using objects to send, receive, display, and input the same kind of data, so I already have objects ready. For a quicker solution you can just use a empty object and add the data to it. If the data is a set of the same type of data then just use an array. However, with a object you have useful names on the server side. Here is a more generic version untested, but passed jslint.
function postUsingJSON() {
// collect elements that hold data on the page, here I have an array
var elms = document.getElementById('parent_id').elements,
// create a post request object
// JDK is a namespace I use for helper function I intend to use in other
// programs or that i use over and over
// makeAjaxPost returns a request object with post header prefilled
req = JDK.makeAjaxPost(),
// create object to hold the data, or use one you have already
dataObj = {}, // empty object or use array dataArray = []
n = elms.length - 1; // last field in form
// next add the data to the object, trim whitespace
// use meaningful names here to make it easy on the server side
dataObj.dataFromField0 = elms[0].value.trim(); // dataArray[0] =
// ....
dataObj.dataFromFieldn = elms[n].value;
// define a callback method on post to use the server response
req.callback = function (text) {
// ...
};
// JDK.makeAjaxPost.call(ULR, data)
req.call('handle_post_on_server.php', JSON.stringify(dataObj));
}
Good Luck.

CoffeeScript implementation returning a GET query string:
serialize = (form) ->
enabled = [].filter.call form.elements, (node) -> not node.disabled
pairs = [].map.call enabled, (node) ->
encoded = [node.name, node.value].map(encodeURIComponent)
encoded.join '='
pairs.join '&'
Or if you rather prefer a key-value map:
serialize = (form) ->
data = {}
for node in form.elements when not node.disabled and node.name
data[node.name] = node.value
data
I haven't looked at jQuery's implementation, so no 100% compatibility guaranteed.