Develop Reference

How do I create a custom javascript variable that selects part of an already existing javascript variable?

I am trying to create a custom javascript variable in GTM that returns part of a javascript variable that already exists.
Variable that already exists: window.ShopifyAnalytics.meta.product.variants.0.name
returns this: "Bamboo Basic String - Schwarz - S"
However I want to code a custom javascript variable to just return the Schwarz part, is this possible? If so what is the code that I would need?
Please can someone let me know what code to put into GTM to create this variable?
TIA

If all names are pretty much the same you could use split to get that part of string and then remove whitespaces. It would look like this:
window.ShopifyAnalytics.meta.product.variants.0.name.split('-')[1].replace(/
/g,'');

If the already existing variable is always structured the same way you could do something like this:
let variable = window.ShopifyAnalytics.meta.product.variants.0.name.split('-')
Then by calling varaible[1] you get the 'Schwartz' part of the variable.

If you want a return value you can use a function like the following and call it wherever you want.
Simply make sure to pass the correct argument content
// Declaring a function getColor that returns the second element in the list,
// trimmed (without spaces before and after)
const getColor = (content) => {
return content.split('-')[1].trim();
}
const test = "Bamboo Basic String - Schwarz - S";
console.log(getColor(test));
//console.log(getColor(window.ShopifyAnalytics.meta.product.variants.0.name));

You could split the string on the hypens (-) like this:
const productName = window.ShopifyAnalytics.meta.product.variants.0.name;
const part = productName.split(' - ')[1];
Assuming you have a consistent format, and you always want the second part after that hyphen.
split will separate parts of a string into an array where it finds a match for the argument. The first index [0] will be the product name, the second [1] will be the part you're looking for.
This could cause issues if you have a product name with a - in it too though so use with care!
If it needs to be an anonymous function for GTM, you could try the following (though I'm not a GTM expert):
function () {
const productName = window.ShopifyAnalytics.meta.product.variants.0.name;
return productName.split(' - ')[1] || 'Unknown';
}

Replace Word Within Word - Javascript

I need to get a id from a html element and replace a part of the word. For example:
HTML
<input type="checkbox" id="facebookCheckbox"></div>
JavaScript
var x = document.getElementById("facebookCheckbox");
var name = x.id;
name.replace("Checkbox","");
This obviously does not work because the replacing word has to be standalone for it to be replaced. Is there a different way of doing this?
I'm looking for purely javascript no jQuery
Thank you!

name.replace("Checkbox","");
This obviously does not work because the replacing word has to be standalone for it to be replaced.
No, it does work and there's no need to be "standalone" - any part of the string can be matched. Only you did nothing with the result of the operation:
console.log(name.replace("Checkbox",""));
// or
name = name.replace("Checkbox","");
// or assign back to x.id maybe?

You are creating a copy of string when replacing, so you must assign the result of .replace() back to x.id.
var x = document.getElementById("facebookCheckbox");
x.id = x.id.replace("Checkbox","");

this is not going to work in this way. However you can have a marker kind of character by which you can break the name into array and implement the logic. For example:
var x = document.getElementById("facebook_Checkbox");
//Note I have added underscore in the Id
var name = x.id;
var arr=name.split("_");
//Now you have Checkbox and Facebook as string objects (part of array) and you can use them
name=arr[0]
I hope it will solve the purpose.

How to add class based on current url

var search_name = location.search;
if (search_name.search("cate_no=24") > 0) {
$(".cate_new a").addClass("active");
}
});
If current document url is http://abc.com/list.html?cate_no=24,
I want to add class "active" into li a.
I searched and found these js code, but it doesn't work.
Is it wrong?

It's incorrect. search() returns the offset position of a match if a match is found, and -1 if a match isn't found.
As you are checking for whether cate_no=24 contains cate_no=24, it will return 0 if true.
Currently, your conditional checks whether the search() will return > 0, which is not what you want.
What you should be doing is check whether it is greater > -1:
if (search_name.search("cate_no=24") > -1)
Although, as I mentioned in the first revision of my answer, it would be better and faster to use indexOf() (search() is supposed to be used when dealing with regular expressions, not for simple string searches).
if (search_name.indexOf("cate_no=24") > -1)

search will only gives you the String. that will be in your case ?cate_no=24
So we leave the first part as it is and try to find the desired value in search_name as string.
var search_name = location.search;
This how we can find the index of the desired pattern.
if (search_name.indexOf("cate_no=24") > 0) {
$(".cate_new a").addClass("active");
}

My personal blog is static so I also had to figure out how to do this without PHP or some other server side code.
This bit of code grabs the path of the current URL, e.g. if you are on http://example.com/about, it would return the string '/about/'. From there you write a simple conditional to add a class to the link you select.
var currentURL = window.location.pathname.toString();
console.log(currentURL);
if (currentURL = '/about/') {
$('a#about').addClass('active')
} else if (currentURL = '/work/') {
...
}
This could be further developed to grab the href attributes from an array of links with a certain class (.nav-items, for example) and add the active class to whichever element has a href equal to the returned string.

Regular Expression in indexOf on javascript

I want get my program parameters from rel attribute of element, first of all is it logical ?
and the rel attribute may contain this string rel="_p|b|w=300|h=200" or rel="_p|w=300"
, so I use split to split my string with | pattern :
var attr = $(this).attr('rel').split('|');
for _p and b there is no problem because I can check with indexOf but for w and h I should use regular expression because the w and h value will be change.
how can I use regular expression in indexOf ?
sorry for my bad English
EDIT:
if (attr.indexOf('b')) {
blank = true;
}

First of all, that isn't a very elegant way of retrieving data. Anyway, if you really want to do that in that way, then you can use regexes as follows:
var matches = $(this).attr('rel').match(/w=(\d+)/);
var w = (matches && matches[1]) || defaultValue;
Also, if there can be multiple elements that end in 'w', then you'd better change your regex to something like:
var matches = $(this).attr('rel').match(/(?:^|\|)w=(\d+)/);

I would have suggested the use of custom attributes as well, however these would not be w3-conform as you want them to.
A simple way would be to split the parameters and then loop through and check each index whether it is one of the attributes you are expecting:
var cust_params = $(this).attr('rel').split('|'); //or this.rel as GGG suggested in a comment?
for(var i=0;i<cust_params.length;i++) {
if('_p'==cust_params[i]) {
//...
}
//...
if(cust_params[i].match(/w=(\d+)/)) {
//you could even do this without a regular expression
}
}
I hope this doesn't violate some good practice that I'm unaware of because I always feel like there must be a more elegant way when I do this kind of thing :) As it is I get a kind of quick-and-dirty feel about this.

Sorry there is no way you can do it in one command with normal javascript, indexOf just doesn't support regular expression.
You can either loop through the array or use jquery supported command for array.
For example: once you have the array attr as you like, you can use jQuery.grep() http://api.jquery.com/jQuery.grep/
a_equal = jQuery.grep(attr, function(a, i){
return (a.match(/=/) and i > 0); // modify this as you like
});
to create an array a_equal with all the assignment argument.
disclaimer.. code not yet tested.

Like Paolo Bergantino I'd also suggest using data-attributes, or you could store the data in a JSON (again, in a data attribute) and parse that:
<a href="#" data-info='{"width": "300", "height": "200", "color": "#fff", "etc": "foo"}'>
var info = JSON.parse(a.getAttribute('data-info'));
Edit: replaced eval with Phrogz's suggestion.
(With eval: eval('(' + a.getAttribute('data-info') + ')'))

Get values from hash in URL using jquery

If I re-rite the URL using :
var id = 150
window.location.hash = "id="+id;
how to get the value of id using jQuery ?

No jQuery needed..
var id = /^#?id=(.+)/.exec(location.hash);
id = id ? id[1] : '';
// OR
var id = location.hash.substr(4); // (when hash can only be #id=..)
// This also selects 123 in #no=123 (!)

+1 for Rob W's answer not to use jQuery for this. But there're two things, i'd like to point out.
1.) Executing a regular expression, plus using a tertiary operator is "overload", too. ;-)
2.) You should consider that some browers return the hash symbol, and some don't!
To avoid to truncate the actual value part, I'd say it's safer to use replace(), instead of substr():
var id = location.hash.replace('id=', '').replace('#', '');
UPDATE:
I think split() is an even better solution:
var id = location.hash.split('id=')[1];
Just one (native) function call, which also "checks" if the request URL actually contains a hash that contains the string "id=idString".
If it does, the value of var id is "idString". If not, value of var id is undefined.