Although, it ran fine on small data. I need help looping through JSON in this form:
var current_value = 2;
json_data = {"2":"first information","3":"Second informaton","4":"Third information"}
What I want to do is get the value in the json_data that corresponds to current_value of 2
The problem is that I keep getting " anytime I run this loop:
for(x in json_data){
if(x === current_value){
extracted = json_data[current_value];
}
}
JavaScript property names are strings. 2 is a number. === does not do type conversion. "2" !== 2.
You should set current_value to "2" instead of 2.
The loop is pointless though.
A more sensible approach would be:
var extracted;
if (current_value in json_data) {
extracted = json_data[current_value];
}
… or even just skip the if statement. extracted will be undefined either way if the property doesn't exist.
Related
I have a simple parse to get the sum of a collection of textareas. It works fine, but if there's no value placed in the field, then the calculation just doesn't run.
How can I make the default value 0 without having the contents actually have to be 0? Like, I don't want the fields to load up with a 0 already waiting in the box - I just want the formula to not worry about empty fields.
Here's the jQuery:
jQuery(document).ready(function(){
jQuery(".button1").click(function(){
var set1 = function() {
var calc1 = 0;
$('.calc1').each( function(index,item) {
calc1 += parseInt(jQuery(item).val());
});
$('.result1').html(calc1);
}
set1();
});
});
The codepen can be seen here if you'd like to get a better idea: https://codepen.io/JTBennett/pen/NENMdP
I appreciate any help with this! I know it's probably a stupid mistake, but I've tried a few different things and not gotten anywhere yet.
Try parseInt(jQuery(item).val() || 0). The || operator will return the second value if the first is falsey. Therefore if the value is empty, it will try to parse '0' which it will successfully.
Just make an if statement that looks for an empty field and then replace it with 0.
$('.calc1').each( function(index,item) {
var itemValue = jQuery(item).val();
if (itemValue === "") {itemValue = 0;}
calc1 += parseInt(itemValue);
});
You can just replace your line with this:
calc1 += parseInt(jQuery(item).val() || 0);
var status = result.locations[index].status;
var operator = result.locations[index].operator;
var original = result.locations[index].original;
var produced = result.locations[index].produced;
var href = result.locations[index].more;
I have the above which each need to be an if statement to check if there is content and my output is the below code.
if (result.locations[index] && result.locations[index].status){
var status = result.locations[index].status;
} else {
var status = '';
}
I would need to reproduce this per line from the code at the top of the post. What would be the best method to simplify each down to keep the code neater and not produce 5 lines of if statement when 1 or 2 would do.
var status = (result.locations[index] && result.locations[index].status ? result.locations[index].status : '');
Not sure why you want to, but:
var status = (result.locations[index] && result.locations[index].status) ? result.locations[index].status : ""
Your problem is trying to access a property of a "deep" javascript object using its path.
This is a common question :
Javascript: Get deep value from object by passing path to it as string
Accessing nested JavaScript objects with string key
There is no built-in way to do this in javascript.
There are plenty of libraries to do that, for example, with selectn, this would become something like (I have not tested it, so I don't know if the index part will work, but you get the idea) :
var status = selectn("locations." + index + ".status", result) || ''
If the structure of your objects is always the one above (that is, the property is just at one level of depth), and you're not expecting 'falsy', you could simply write the 'test' function yourself :
function safeGet(instance, propertyName, defaultValue) {
// As pointed by AlexK, this will not work
// if instance[propertyName] can be anything Falsy ("", 0, etc...)
// If it's possible, get a library that will do
// the full series of insane checks for you ;)
if (instance && instance[propertyName)) {
return instance[propertyName];
} else {
return defaultValue;
}
}
var location = result.locations[index]; // Potentially undefined, but safeGet will deal with it
var status = safeGet(location, "status", "");
var operator = safeGet(location, "operator", "DEFAULT_OPERATOR");
...
var status = result.locations[index] && result.locations[index].status || '';
However, better maje sure before, if result.locations[index] exists... else do whatever is to be done in your code..
I have a big question.
I have many Strings in my Programm and want to check these Strings on there values.
I wrote a Loop for it, but insted of the Definition of an String he is creating a new value. It's basicly really difficult to discribe, also because i am basicly German.
But i can give you my current code, so maybee you will see what I mean:
{
var Loch1G = $('#m1-Rundenanalyse-Datum').val(); //In the strings just the number is changing
var Loch2G = $('#m1-Rundenanalyse-Turnier').val();
x=1
while (x <= 2) {
if ("Loch" + x + "G" == ""){ //Next String is genrated (x=x+1)
alert("Eingabe war leer");
}
x=x+1
}
}
How can I solve this?
I'd suggest using an array to store the values you want to check:
var lochs = [];
lochs.push($('#m1-Rundenanalyse-Datum').val());
lochs.push($('#m1-Rundenanalyse-Turnier').val());
for (var i = 0, len = lochs.length; i < len; i++){
if (lochs[i] == ''){
alert("Eingabe war leer");
}
}
JS Fiddle demos: passes (no alert), fails (alert)
This suggestion is based on my presumption that you're trying to create the names of the vars you want to check, which won't work, whereas this approach lets you store all values (however many) in the same array and then iterate over that array to find any values that are equal to an empty string.
If you really want to stick with your current approach, you could do the following:
{
window.Loch1G = $('#m1-Rundenanalyse-Datum').val(); //In the strings just the number is changing
window.Loch2G = $('#m1-Rundenanalyse-Turnier').val();
var x=1;
while (x <= 2) {
if (window["Loch" + x + "G"] == ""){ //Next String is genrated (x=x+1)
alert("Eingabe war leer");
}
x=x+1;
}
}
But I can't think why you'd want to; plus the use of global variables is poor practice as it explicitly makes those variables available to every closure within the document, which allows them to be easily, and accidentally, overwritten.
In a reasonably up-to-date browser, that implements Array.prototype.every, you could dispense with the explicit iteration:
var lochs = [];
lochs.push($('#m1-Rundenanalyse-Datum').val());
lochs.push($('#m1-Rundenanalyse-Turnier').val());
if (!lochs.every(function(a){ return a !== ''; })) {
alert("Eingabe war leer");
}
JS Fiddle demos: passes (no alert), fails (alerts).
I have piece of JavaScript code which cycles through form elements and builds an object.
I have a mixture of HTML input fields and ASP.NET input fields. ASP.NET changes the ID of the fields to the form xxxxx_yyyy_id, so I am attempting to use the split function to extract the original id.
// Iterate over all the text fields and build an object
$(':text').each(function () {
var tokens = this.id.split("_");
if (tokens.length = 3) {
// Assume this is a .net inputbox - extract the original id
inFormData[tokens[2]] = this.value;
} else {
inFormData[this.id] = this.value;
}
});
Stepping through the above code, the first id is ctl00_ContentPlaceHolderCol1_forenameField, so the tokens.length = 3 code is run.
On the second iteration, the id is forenameField2 so I would expect the tokens.length to be 1, but it is actually 3. The else statement is never run.
This could be something simple, but I cant work it out. If I inspect the tokens array it has only 1 element in on the second iteration. I have also tried setting the array.length to 0 after each iteration.
Any help appreciated.
Correct this:
== instead of =. === is more better
if (tokens.length == 3) {
// Assume this is a .net inputbox - extract the original id
inFormData[tokens[2]] = this.value;
} else {
inFormData[this.id] = this.value;
}
Change your = 3 to === 3
At the moment you're overwriting tokens.length every time.
NB: === is preferred to == because it's an exact equality check. The two-equals version will attempt to cast the two operands to the same type before comparison, which is 1. unnecessary, 2. inefficient, 3. sometimes error prone.
That is why you should always put the constant first when testing. If you forget a comparison sign it will throw an error:
if( 3 = tokens.length ) // throws an error
if( 3 == tokens.length ) // ok
if( 3 === tokens.length) // ok
from:
if (tokens.length = 3) {
to:
if (tokens.length == 3) {
This is probably easy for someone.
I am returning a list of campaignIDs (12,45,66) via JSON to a javascript variable
var campaignList = res.DATA.CAMPAIGNS
Now, given a specified campaignID passed in the URL
var campaignId ='<cfoutput>#url.campaignID#</cfoutput>'
I want to check if the returned list contains this campaignID
Any help much appreciated.
Plenty of ways to do it, but I like nice data structures, so ...
Split the list on comma, then loop over list, looking for value:
function campaignExists(campaignList,campaignId) {
aCampaignList = campaignList.split(',');
for (i=0;i<aCampaignList.length;i++) {
if (aCampaignList[i]==campaignId)
return true;
}
return false;
}
Since Array.indexOf sadly isn't cross browser, you're looking at something like:
// assume there is no match
var match_found = false;
// iterate over the campaign list looking for a match,
// set "match_found" to true if we find one
for (var i = 0; i < campaignList.length; i += 1) {
if (parseInt(campaignList[i]) === parseInt(campaignId)) {
match_found = true;
break;
}
}
If you need to do this repeatedly, wrap it in a function
Here's a bit of a "out of the box" solution. You could create a struct for your property id's that you pass into the json searilizer have the key and the value the same. Then you can test the struct for hasOwnProperty. For example:
var campaignIDs = {12 : 12, 45 : 45, 66 : 66};
campaignIDs.hasOwnProperty("12"); //true
campaignIDs.hasOwnProperty("32"); //false
This way if the list is pretty long you wont have to loop through all of the potential properties to find a match. Here's a fiddle to see it in action:
http://jsfiddle.net/bittersweetryan/NeLfk/
I don't like Billy's answer to this, variables within the function have been declared in the global scope and it is somewhat over complicated. If you have a list of ids as a string in your js just search for the id you have from user input.
var patt = new RegExp("(^|,)" + campaignId + "(,|$)");
var foundCampaign = campaignList.search(patt) != -1;