Ruby and Javascript: passing a Ruby array as a Javascript variable

Question

I'm trying to dynamically draw a Google Map and place a marker on it. In my controller, I assemble an array containing the name of the businesss, latitude, longitude and a z-index.

I have an array in Ruby that is available to my Rails view:

@locations = [["Location One",36.0552,-114.928,1]]

When I try to use that array in some Javascript:

var loc = <%= @locations %>

I see this in view source:

var loc = [["Location One",36.0552,-114.928,1]]

In order for the map to display the variable needs to read like:

var loc = [['Location One',36.0552,-114.928,1]]

With the quotes intact around the first element of the array. If I hard code that last line into the Javascript the map renders correctly. It really seems to be the quot; tags that are messing things up.

There will be more than one location on the map so I thought an array of arrays would be the best way to get the needed data into my view.

How can I accomplish this? Thanks.

Answer 1

Edit Corrected following DNNX's comment.

I think you need to convert it to json (a subset of JavaScript) before rendering:

require "json"
...
var loc = <%= @locations.to_json.html_safe %>

• DNNX: <%= @locations.to_json %> doesn't work. <%= @locations.to_json.html_safe %> does.
• svf: I didn't know about html_safe. Thanks guys.

Answer 2

you need to use html_safe to prevent the escape the quote

• ohmu: Providing a simple example would be useful.