module Katex

Provides a Ruby wrapper for KaTeX server-side rendering.

Constants

KATEX_VERSION
VERSION

Attributes

execjs_runtime[RW]

The ExecJS runtime factory, default: `-> { ExecJS.runtime }`. Set this before calling any other methods to use a different runtime.

This proc is guaranteed to be called at most once.

Public Class Methods

gem_path() click to toggle source

# File lib/katex.rb, line 65
def gem_path
  @gem_path ||=
    File.expand_path(File.join(File.dirname(__FILE__), '..'))
end

katex_context() click to toggle source

# File lib/katex.rb, line 54
def katex_context
  @load_context_mutex.synchronize do
    @context ||= @execjs_runtime.call.compile File.read katex_js_path
  end
end

katex_js_path() click to toggle source

# File lib/katex.rb, line 60
def katex_js_path
  File.expand_path File.join('vendor', 'katex', 'javascripts', 'katex.js'),
                   gem_path
end

render(math, display_mode: false, throw_on_error: true, error_color: ' click to toggle source

Renders the given math expression to HTML via katex.renderToString.

@param math [String] The math (Latex) expression @param display_mode [Boolean] Whether to render in display mode. @param throw_on_error [Boolean] Whether to raise on error. If false,

renders the error message instead (even in case of ParseError, unlike
the native katex).

@param error_color [String] Error text CSS color. @param render_options [Hash] Additional options for katex.renderToString.

See https://github.com/Khan/KaTeX#rendering-options.

@return [String] HTML. If strings respond to html_safe, the result will be

HTML-safe.

@note This method is thread-safe as long as your ExecJS runtime is

thread-safe. MiniRacer is the recommended runtime.

# File lib/katex.rb, line 30
def render(math, display_mode: false, throw_on_error: true,
           error_color: '#cc0000', macros: {}, **render_options)
  maybe_html_safe katex_context.call(
    'katex.renderToString',
    math,
    displayMode: display_mode,
    throwOnError: throw_on_error,
    errorColor: error_color,
    macros: macros,
    **render_options
  )
rescue ExecJS::ProgramError => e
  raise e if throw_on_error

  render_exception e, error_color
end

Private Class Methods

maybe_html_safe(html) click to toggle source

# File lib/katex.rb, line 84
def maybe_html_safe(html)
  if html.respond_to?(:html_safe)
    html.html_safe
  else
    html
  end
end

render_exception(exception, error_color) click to toggle source

# File lib/katex.rb, line 72
    def render_exception(exception, error_color)
      maybe_html_safe <<~HTML
        <span class='katex'>
          <span class='katex-html'>
            <span style='color: #{error_color}'>
              #{ERB::Util.h exception.message.sub(/^ParseError: /, '')}
            </span>
          </span>
        </span>
      HTML
    end