Rails 4: Passing variables to javascript
Solution 1
I used to do:
var my_var = <%= User.count %>
console.log(my_var)
If it is an integer this works just fine. If, however, you want to pass objects, then use:
var my_var = JSON.parse(('<%= (@Users.count) == 0 ? "[]" : Users.first(10).to_json %>')
console.log(JSON.stringify(my_var))
Solution 2
You forgot about document ready. Try:
$(function(){
var datadump = ($('#trackers').data('trackers'));
console.log(datadump)
});
Or for provide data from Rails to JS use Gon gem https://github.com/gazay/gon
Seph Cordovano
Updated on July 17, 2022Comments
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Seph Cordovano almost 2 years
I've tried numerous methods and followed Ryan Bates' guide but no matter what I do I still get undefined.
application.html.erb
<body> <%= content_tag :div, id: 'trackers', data: {trackers: User.count} do %> <% end %> </bodyapplication.js.erb
var datadump = ($('#trackers').data('trackers')) console.log(datadump) //returns undefined in consoleViewing page source I can see the variable
<div data-trackers="2" id="trackers">I'm passing User.count for now just to keep it simple but I'll need to be passing @trackers_count which is instantiated in a before_action in the application controller. I should be able to sort that out though once I figure out the problem here. Any suggestions?
UPDATE - I've simplified all variables down to just trackers, instead of trackers_count to prevent any errors from syntax and updated code here to reflect that.
ANSWER UPDATE - I selected the correct answer because if you want to pass any variables ASIDE FROM CURRENT_USER those methods worked perfectly. However, you can't access anything with current_user in JS because it loads before the window, so it can't know who the current_user is. It's a real pain but I just did it the long way and accessed the info I need through passing in json and an ajax requests.