# KaTeX for Ruby [![Build Status](https://travis-ci.org/glebm/katex-ruby.svg?branch=master)](https://travis-ci.org/glebm/katex-ruby) [![Test Coverage](https://codeclimate.com/github/glebm/katex-ruby/badges/coverage.svg)](https://codeclimate.com/github/glebm/katex-ruby/coverage) [![Code Climate](https://codeclimate.com/github/glebm/katex-ruby/badges/gpa.svg)](https://codeclimate.com/github/glebm/katex-ruby)

This rubygem enables you to render TeX math to HTML using [KaTeX].
It uses [ExecJS] under the hood.

## Installation

Add this line to your application's Gemfile:

```ruby
gem 'katex', '~> 0.4.0.beta'
```

And then execute:

    $ bundle

Or install it yourself as:

    $ gem install katex

## Usage

Render some math:

```ruby
Katex.render 'c = \\pm\\sqrt{a^2 + b^2}'
#=> "<span class=\"katex\">..."
```

If you're on Rails, the result is marked as `html_safe`.

Any error in the markup is raised by default. To avoid this and render error
text instead, pass `throw_on_error: false`:

```ruby
Katex.render '\\', throw_on_error: false
```

Note that this will catch even `ParseError`s (unlike native KaTeX).

Learn more about all the available options in the
[documentation](http://www.rubydoc.info/gems/katex/Katex#render-class_method).

### Assets

For this rendered math to look nice, you will also need to include KaTeX CSS
into the webpage.

I recommend you use the CSS bundled with this gem, to ensure version
compatibility.

If you use Rails, Sprockets without Rails, or Hanami, the assets are registered
automatically and you simply need to `//= require katex` if you use CSS
or `@import "_katex"` if you use Sass.

You can also `//= require katex` in your JS to access the KaTeX renderer in the
browser.

If you don't use Rails, you can find the assets in the `vendor/assets`
directory of the gem (`File.join(Katex.gem_path, 'vendor', 'assets')`).

### Caching

If you cache the output of `Katex.render`, make sure to use the KaTeX
version in the cache key, as the output may change between versions.

You can get the KaTeX version bundled with this gem via:

```ruby
Katex::KATEX_VERSION
```

## 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](https://rubygems.org).

## Contributing

Bug reports and pull requests are welcome on GitHub at
https://github.com/glebm/katex.

This project is intended to be a safe, welcoming space for collaboration,
and contributors are expected to adhere to the
[Contributor Covenant](http://contributor-covenant.org) code of conduct.


## License

The gem is available as open source under the terms of the
[MIT License](http://opensource.org/licenses/MIT).


[KaTeX]: https://github.com/Khan/KaTeX
[ExecJS]: https://github.com/rails/execjs