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JSON.parse() returning strings

I am trying to iterate through an array of objects and populate an HTML select element with options whose values are the entire contents of each object. The population is successful, but the objects are turned into strings in the process and I do not know how to turn them back into objects.
Running them through JSON.parse() gives me "Uncaught SyntaxError: Unexpected token o in JSON at position 1 at JSON.parse." My research suggests that this happens when you use JSON.parse() on something that is already an object, but running typeOf() on the data beforehand reveals that it is a string.
I do not get this error if I instead run the data through JSON.parse(JSON.stringify(data)), but its output remains a string.
Please help me understand what I am misapprehending about JSON.parse(). Thank you.
const selectors = document.getElementsByClassName("ingredientSelector");
const cookButton = document.getElementById("cookButton");
//very large array of ingredient objects
let selectorOptions = "<option value = 'Nothing'>Nothing</option>";
for (let i = 0; i < ingredients.length; i++){
selectorOptions += ("<option value = '" + ingredients[i] + "'>" + ingredients[i].name + "</option>");
}
Array.prototype.forEach.call(selectors,function(selector){
selector.innerHTML = selectorOptions;
});
function cook(ingredients){
console.log("Cooking with ingredients: " + ingredients);
}
cookButton.addEventListener("click", function(){
let ingredients = [];
Array.prototype.forEach.call(selectors,function(selector){
if(selector.value !== 'Nothing'){
console.log(typeof(selector.value))
JSON.parse(selector.value);
let JSONString = JSON.stringify(selector.value);
console.log(typeof(JSONString));
let JSONObject = (JSON.parse(JSONString));
console.log(typeof(JSONObject));
console.log(JSONObject.name);
}
console.log(ingredients);
cook(ingredients);
});
});

The issue is how you're building the value properties for the options you're inserting into each selector. On this line:
selectorOptions += ("<option value = '" + ingredients[i] + "'>" + ingredients[i].name + "</option>");
Your comment says that ingredients is an array of objects, so ingredients[i] will be an object. Concatenating an object to a string will, by default, turn it into [object Object] - and this is what's causing your error. You're ending up with an option that looks something like this, perhaps:
<option value = '[object Object]'>Raw Prime Meat<object>
There's two perfectly valid approaches here. You can either store the ingredient index in the option values, which you can then use to lookup the ingredient from your master array later, or you should use JSON.stringify(ingredients[i]) to turn the object into a JSON.parseable string to make your code work as-is.
So this would work fine:
selectorOptions += ("<option value = '" + JSON.stringify(ingredients[i]) + "'>" + ingredients[i].name + "</option>");

JavaScript loop through JSON data and print in html

I'm new to JavaScript and I'm trying to figure out how-to loop through JSON and print each selected value in HTML. My solution below does everything I want except print "all" rows of the JSON data. It only prints the last one. I've been researching on StackOverflow and elsewhere, but I'm not finding the solution. Sorry if this is a redundant question and thank you for your help!
//Fetch JSON from URL
//https://developer.mozilla.org/en-US/docs/Web/API/Fetch_API/Using_Fetch
fetch('https://s.codetasty.com/toddbenrud/sandBoxToddBenrud/example/songData.json')
.then(function(response) {
return response.json();
})
.then(function(myJson) {
var songData = (JSON.stringify(myJson));
//https://stackoverflow.com/questions/9329446/for-each-over-an-array-in-javascript
var index;
var obj = JSON.parse(songData);
for (index = 0; index < obj.length; ++index) {
var student_name = obj[index]['name'];
var student_email = obj[index]['email'];
var song_name = obj[index]['song'];
var song_url = obj[index]['url'];
document.getElementById("studentName").innerHTML = '<br>'+student_name;
document.getElementById("studentEmail").innerHTML = '<br>'+student_email;
document.getElementById("songTitle").innerHTML = '<br>'+song_name;
document.getElementById("songURL").innerHTML = '<br>'+song_url;
}
});

Inside your for loop you are reassigning your elements' content in every Iteration. It means that you fill your elements with the First item of the Array on the First time you run the for, but the Second time you run It, you replace the elements' content with the Second item of the Array. So you get only the Last Item Data.
To solve this problema, you should "increment" your element's content on each Iteration, instead of replace it. To achieve that, you replace the Lines like
document.getElementById("studentName").innerHTML = '<br>'+student_name;
With
document.getElementById("studentName").innerHTML += '<br>'+student_name;
The += operator does a concatenation on strings

Becasue you set string for elements, don't add string.
Replace from:
document.getElementById("studentName").innerHTML = '<br>'+student_name;
document.getElementById("studentEmail").innerHTML = '<br>'+student_email;
document.getElementById("songTitle").innerHTML = '<br>'+song_name;
document.getElementById("songURL").innerHTML = '<br>'+song_url;
To:
document.getElementById("studentName").innerHTML += '<br>'+student_name;
document.getElementById("studentEmail").innerHTML += '<br>'+student_email;
document.getElementById("songTitle").innerHTML += '<br>'+song_name;
document.getElementById("songURL").innerHTML += '<br>'+song_url;

Loop through Array and count

Been struggling with counting through this array. I was able to do it previously but I don't think I quite understand how the parameters of a function are assigned its data.
I am bringing in an array with from JSON data over AJAX, then using a .each loop to go through the data and count it. But I can't seem to count it when using the index parameter. It is just giving me the actual objects and not counting how many objects there are.
I was hoping that someone could help me understand why I am getting the object and not the count of objects in the array. What I have now is just my final attempt at getting it to count, I know it's wrong.
I am trying to count how many "results" there are in the array (that came from the JSON file).
I have added snippets of my code and attached a link to the JSON file. I have also marked the problem area with a comment saying Problem Area
CODE -
$.getJSON('http://api.fixer.io/latest?base=ZAR', {
action: "query",
list: "search",
format: "json",
}
, function (data) {
var baseCurr = data.base;
var baseDate = data.date;
$('#curr-cont').append('<div class="base row1" id="row1"><div class="base flag" id="flag"><i class="famfamfam-flag-za"></i></div><div class="base country-name"><p class="c-name" id="count-name">' + baseCurr + '</p></div><div class="base currency"><p class="c-amount" id="curr">' + baseDate + '</p></div></div>');
//***Problem Area***
var rates = [data];
$.each(rates[0], function (i, obj) {
console.log(obj);
});
$.each(data.rates, function (i, item) {
var amount = [item];
var name = [i];
var maxLength = 4;
var string = amount.toString();
string = string.substr(0, maxLength);
// amount = amount.substr(0, maxLength);
$('#curr-cont').append('<div class="row1" id="row1"><div class="flag" id="flag"><i class="famfamfam-flag-' + name + '"></i></div><div class="country-name"><p class="c-name" id="count-name">' + name + '</p></div><div class="currency"><p class="c-amount" id="curr">' + string + '</p></div></div>');
// if(i > 0){
// $('#list1').append('<li>' + name + '</li>');
// }
// else{
// $('#list2').append('<li>' + name + '</li>');
// }
});
});
JSON Data File

edit:
since rates is an object and not an array, you can do: Object.keys(data.rates).length.
Object.keys(...) will give you an array with all the keys in the object.
original:
If you want to know the number of rates in that file: data.rates.length will give you the length of the rates Array that is returned in the data.
No need to count it

Javascript Multidimensional Array is Empty

I think Im misunderstanding something here - I normally work in PHP and think I'm missing something small. My final array tmp is empty and displays as ",,,,,,,,,,,,,,,,". It seems to me my tmp array might be emptied somewhere or the scope gets reset for some reason. I'm using this as coordinates from a table where you can select table rows and posting to a webservice but my array seem to be erroneous.
var length = $("#arrayCount").html();
var letters = ["A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z"];
var col = getSelectedColumn(); //for example sake lets say "B" is the selected column
var row = getSelectedRow(); //selected rows will be from "11" - "16"
var columnIndexStart = letters.indexOf(col[0]);
var tmp = [];
for(var i = row[0]; i <= row[1]; i++) //rows[0] = 11 and rows[1] = 16
{
tmp[i] = [];
for(var j = columnIndexStart; j < letters.length; j++) //columns and starts at index 1 if we work with "B"
{
var val = $("#" + i + "_" + letters[j]).html(); //using the row and letters as the associated DOM elements ID. Easier to retrieve it's HTML then.
if(val != undefined)
{
console.log("Index [" + i + "]['" + letters[j] + "'] = " + val); //works perfectly and prints as it should.
tmp[i]['"'+letters[j]+'"'] = val; //using quotes to save letters? Is this preferred?
}
}
}
console.log('Final Array: ' + tmp); //empty??
console.log('Final Array: ' + tmp[14]['G']); //testing HTML output. But is undefined.
return tmp;
Any help will be greatly appreciated.
Edited:
Example of console output.

My final array tmp is empty and displays as ",,,,,,,,,,,,,,,,"
With non-numeric index you are setting the field of object and not the element for index.
If you will have two-dimensional numeric array with numeric indices like the following:
var tmp = [[1,2,3], [1,2,3]];
after console.log('tmp = ' + tmp); you will obviously get the output string like:
tmp = 1,2,3,1,2,3
Because when you are trying to convert array to string it converts it elements to string and represent them with a commas.
However when you are trying to set element with non-numeric index, you are setting the field of this object.
var tmp = [];
tmp['A'] = 123;
console.log("tmp = " + tmp); // tmp =
console.log(tmp.A); //123
So, console.log in your case works good - it is serializing all elements of two-dimensional array. But no one array of the second level does not have stored values, it has only fields, which are not included in the string representation of array.
You are getting a set of commas, because each sub-array of tmp array does not contains any element, so it's string representation is an empty string. Each sub-array contains the required data into it's fields.
When you are performing sum operation of string and object you are forcing object to convert to string representation. Instead of this it is recommended to use console.log(yourObj) - it will log the whole object without converting it to string.
//using quotes to save letters? Is this preferred?
No, "A" and A are different identifiers.
var s = new Object();
s['"A"'] = 123;
console.log(s['A']); //undefined
console.log(s['"A"']); //123
Additionally, if you will set fields with quotes - you can not get the field in normal style:
console.log(s."A"); //syntax error : expected identifier after '.'

You can also just do this (use comma, not plus):
console.log('Final Array: ', tmp); //empty??
console.log('Final Array: ', tmp[14]['G']);

JSON to HTML using JSON.parse undefined error

When trying to parse the JSON
[{"title":"First Item","href":"first","children":[{"title":"Sub First Item","href":"sub"}]},{"title":"Second Item","href":"home"}]
into a list for navigation its just returning undefined.
I was using code from another answer which was working fine with hardcoded JSON but when using it from a textbox (as its going to be generated using jquery.nestable.js) it just gived undefined and i cant see why, ive tried escaping the quotation marks too but no luck there.
function convertNav(){
var data = document.getElementById('jsonNav').value;
var jsn = JSON.parse(document.getElementById('jsonNav').value);
var parseJsonAsHTMLTree = function(jsn){
var result = '';
if(jsn.title && jsn.children){
result += '<li>' + jsn.title + '<ul>';
for(var i in jsn.children) {
result += parseJsonAsHTMLTree(jsn.children[i]);
}
result += '</ul></li>';
}
else {
result += '<li>' + jsn.title + '</li>';
}
return result + '';
}
var result = '<ul>'+parseJsonAsHTMLTree(jsn)+'</ul>';
document.getElementById('convertedNav').value = result;
}
Ive put it in a jsfiddle
http://jsfiddle.net/nfdz1jnx/

Your code handles only a single Javascript object but, according to your code, all nodes and sub-nodes are wrapped inside Javascript arrays. You can use Array.prototype.forEach to handle the array objects.
Sample code follows.
function convertNav() {
var data = document.getElementById('seriaNav').value;
var jsn = JSON.parse(document.getElementById('seriaNav').value);
var parseJsonAsHTMLTree = function(jsn) {
var result = '';
jsn.forEach(function(item) {
if (item.title && item.children) {
result += '<li>' + item.title + '<ul>';
result += parseJsonAsHTMLTree(item.children);
result += '</ul></li>';
} else {
result += '<li>' + item.title + '</li>';
}
});
return result + '';
};
var result = '<ul>' + parseJsonAsHTMLTree(jsn) + '</ul>';
document.getElementById('convertedNav').value = result;
}
<textarea class="span7" style="width:400px;height:100px;" id="seriaNav">[{"title":"First Item","href":"first","children":[{"title":"Sub First Item","href":"sub"}]},{"title":"Second Item","href":"home"}]</textarea>
<hr />
<button class="btn btn-primary" onClick="convertNav();return false;">Convert</button>
<hr />
<textarea class="span5" style="width:400px;height:100px;" id="convertedNav"></textarea>

Your jsn variable is an array. You're getting a list of Objects back and you'll need to parse each one.
Add this after you get jsn back and you'll see an example of retrieving your data.
alert(jsn[0].title);

Your JSON is parsed into an array of objects. With this in mind, your paths to extract information are wrong. For example, you have:
if(jsn.title...
...whereas there is no jsn.title. There is, however, json[0].title.
Basically, you're missing a loop, over the objects. After
var result = '';
add
for (var i=0, len=jsn.length; i
...and in code subsequent to that change all references to jsn to jsn[i]
And of course close the loop further down.
(Finally, at the risk of being pedantic, jsn is not the best name for the var; it's not JSON anymore; it used to be, but now it's parsed, so it's an array. JSON is a string.)

[{"title":"First Item","href":"first","children":[{"title":"Sub First Item","href":"sub"}]},{"title":"Second Item","href":"home"}]
This is not JSON, this is an array of objects. You don't need to parse this. It's already parsed. It's a javascript object.
You should be able to just parse it like you would a regular object.
data[0].title
data[0].children[1].title
etc.