BenchmarkToJs

This gem allows you to benchmark render times for sections of views and partials, and outputs those times to the Javascript console.

Installation

Add this line to your application's Gemfile:

gem 'benchmark_to_js'

And then execute:

$ bundle

Or install it yourself as:

$ gem install benchmark_to_js

Configuration

By default, the benchmarking will only run in the Rails development environment, however this behaviour can be overridden in an initializer along with several other settings.

# config/initializers/benchmark_to_js.rb
BenchmarkToJs.configure do |config|
  config.run_in_environments = [:development, :staging] # default [:development]

  # see below for examples on pretty enabled/disabled output
  config.pretty = true # default true

  # the following only apply if pretty if set to true
  # minimum milliseconds before time is highlighted in respective colour
  config.red_threshold = 1000   # default 500
  config.orange_threshold = 200 # default 100

  # options that will be passed to `javascript_tag`
  # takes anything that responds to `call`
  # first argument will be the context in which you called `benchmark_to_js` (most likely your view), so any instance methods available there are available here
  config.tag_options = lambda {|ctx| {nonce: ctx.content_security_policy_script_nonce} }
end

Please note that it is NOT recommended to configure this gem to run your production environment!

Usage

To use, just wrap a section of a view in a benchmark_to_js(name) block, like so:

ERB

<%= benchmark_to_js("my content") do %>
  <h1>Some Header</h1>
  <%= some_intensive_methods %>
  ...
<% end %>

Haml

= benchmark_to_js("my content") do
  %h1 Some Header
  = some_intensive_methods
  ...

Both methods will render the content as if it wasn't in the block, and a line will be logged to the Javascript console: 'my content' ran in 123.456ms.

If pretty formatting is enabled (it is by default) then your output will look something like this:

and if it isn't, well then it will look bland, like this:

That's all there is to it!

Development

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/daveallie/benchmark_to_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.