render_as_js

RenderAsJs

Simple Rails helper to render a ruby hash to a ES5/JavaScript object. While a hash like {a:2} in ruby looks like an acceptable object in JS-terms, {a:2}.to_s renders to a string something along the lines of {:a=>2}. Which fails badly in any JS-interpreter. So try {a:2}.to_json and parse it in JS. Might work 90% of the time, but not for e.g. Dates (which turn into strings, which need to be re-evaluated without type-information at the frontend before further interpretation).

Besides converting ruby's Hashes, this gem attempts to rerender the following things nicely in JS:

• Strings
• Date(Time)s
• Numbers
• Symbols
• Booleans
• nils

Note: this is no attempt to recompile ruby to JavaScript, I don't want to get near there.

Alternative

This almost does the same trick: let data = JSON.parse(<%= @data.to_json %>). Sadly that doesn't work very nicely for dates.

Warning

While sanitizing is done using the Rails sanitize helper; be really careful when passing unknown data through this gem (numbers and dates will (probably) be fine, but be careful with strings).

Installation

Add this line to your application's Gemfile:

gem 'render_as_js'

And then execute:

$ bundle

Or install it yourself as:

$ gem install render_as_js

Usage

In your views try:

complex_hash = [{y: 12, x:Date.new(2017,1,1)}, {y: 12, x: Date.new(2017,1,2)}]
render_as_js complex_hash

This should output in your generated html:

[{y: 12, x: new Date('2017-01-01')}, {y: 12, x: new Date('2017-01-02')}]

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/murb/render_as_js. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

License

The gem is available as open source under the terms of the MIT License.