Rails js.erb file cannot find method “render”

Question

I've got the following code in a Javascript ERB file:

$(document).ready(function() {
  $("#workout-week").append(
    <%= escape_javascript(render :partial => "show_training_period", :locals => { :period => @period }) %>
  );
});

When I got to the view, I get the following error:

undefined method `render' for #<#<Class:0x00000004e21158>:0x00000005dbfe98>

The partial exists, and the local variable is non-nil. Any idea why this might happen?

Stack trace:

app/assets/javascripts/slider.js.erb:2:in `evaluate_source'
tilt (1.3.3) lib/tilt/template.rb:209:in `instance_eval'
tilt (1.3.3) lib/tilt/template.rb:209:in `evaluate_source'
tilt (1.3.3) lib/tilt/template.rb:144:in `cached_evaluate'
tilt (1.3.3) lib/tilt/template.rb:127:in `evaluate'
tilt (1.3.3) lib/tilt/template.rb:76:in `render'
sprockets (2.0.3) lib/sprockets/context.rb:175:in `block in evaluate'
sprockets (2.0.3) lib/sprockets/context.rb:172:in `each'
sprockets (2.0.3) lib/sprockets/context.rb:172:in `evaluate'
sprockets (2.0.3) lib/sprockets/bundled_asset.rb:171:in `build_dependency_context_and_body'
sprockets (2.0.3) lib/sprockets/bundled_asset.rb:135:in `dependency_context'
sprockets (2.0.3) lib/sprockets/bundled_asset.rb:194:in `build_dependencies_paths_and_assets'
sprockets (2.0.3) lib/sprockets/bundled_asset.rb:141:in `dependency_paths'
sprockets (2.0.3) lib/sprockets/bundled_asset.rb:61:in `mtime'
sprockets (2.0.3) lib/sprockets/asset.rb:58:in `block in encode_with'
sprockets (2.0.3) lib/sprockets/asset.rb:57:in `each'
sprockets (2.0.3) lib/sprockets/asset.rb:57:in `encode_with'
sprockets (2.0.3) lib/sprockets/bundled_asset.rb:43:in `encode_with'
sprockets (2.0.3) lib/sprockets/caching.rb:52:in `cache_asset'
sprockets (2.0.3) lib/sprockets/environment.rb:82:in `build_asset'
sprockets (2.0.3) lib/sprockets/base.rb:99:in `find_asset'
sprockets (2.0.3) lib/sprockets/environment.rb:72:in `find_asset'
sprockets (2.0.3) lib/sprockets/base.rb:110:in `[]'
sprockets (2.0.3) lib/sprockets/bundled_asset.rb:200:in `block in build_dependencies_paths_and_assets'
sprockets (2.0.3) lib/sprockets/bundled_asset.rb:194:in `each'
sprockets (2.0.3) lib/sprockets/bundled_asset.rb:194:in `build_dependencies_paths_and_assets'
sprockets (2.0.3) lib/sprockets/bundled_asset.rb:141:in `dependency_paths'
sprockets (2.0.3) lib/sprockets/bundled_asset.rb:61:in `mtime'
sprockets (2.0.3) lib/sprockets/asset.rb:58:in `block in encode_with'
sprockets (2.0.3) lib/sprockets/asset.rb:57:in `each'
sprockets (2.0.3) lib/sprockets/asset.rb:57:in `encode_with'
sprockets (2.0.3) lib/sprockets/bundled_asset.rb:43:in `encode_with'
sprockets (2.0.3) lib/sprockets/caching.rb:52:in `cache_asset'
sprockets (2.0.3) lib/sprockets/environment.rb:82:in `build_asset'
sprockets (2.0.3) lib/sprockets/trail.rb:102:in `find_asset_in_path'
sprockets (2.0.3) lib/sprockets/base.rb:101:in `find_asset'
sprockets (2.0.3) lib/sprockets/environment.rb:72:in `find_asset'
sprockets (2.0.3) lib/sprockets/base.rb:110:in `[]'
actionpack (3.1.0) lib/sprockets/helpers/rails_helper.rb:124:in `asset_for'
actionpack (3.1.0) lib/sprockets/helpers/rails_helper.rb:28:in `block in javascript_include_tag'
actionpack (3.1.0) lib/sprockets/helpers/rails_helper.rb:27:in `collect'
actionpack (3.1.0) lib/sprockets/helpers/rails_helper.rb:27:in `javascript_include_tag'
app/views/layouts/application.html.haml:7:in `_app_views_layouts_application_html_haml__2778507683501201875_51020080'
actionpack (3.1.0) lib/action_view/template.rb:144:in `block in render'
activesupport (3.1.0) lib/active_support/notifications.rb:55:in `instrument'
actionpack (3.1.0) lib/action_view/template.rb:142:in `render'
actionpack (3.1.0) lib/action_view/renderer/template_renderer.rb:52:in `render_with_layout'
actionpack (3.1.0) lib/action_view/renderer/template_renderer.rb:38:in `render_template'
actionpack (3.1.0) lib/action_view/renderer/template_renderer.rb:12:in `block in render'
actionpack (3.1.0) lib/action_view/renderer/abstract_renderer.rb:22:in `wrap_formats'
actionpack (3.1.0) lib/action_view/renderer/template_renderer.rb:9:in `render'
actionpack (3.1.0) lib/action_view/renderer/renderer.rb:36:in `render_template'
actionpack (3.1.0) lib/action_view/renderer/renderer.rb:17:in `render'
actionpack (3.1.0) lib/abstract_controller/rendering.rb:120:in `_render_template'
actionpack (3.1.0) lib/action_controller/metal/streaming.rb:250:in `_render_template'
actionpack (3.1.0) lib/abstract_controller/rendering.rb:114:in `render_to_body'
actionpack (3.1.0) lib/action_controller/metal/renderers.rb:30:in `render_to_body'
actionpack (3.1.0) lib/action_controller/metal/compatibility.rb:43:in `render_to_body'
actionpack (3.1.0) lib/abstract_controller/rendering.rb:99:in `render'
actionpack (3.1.0) lib/action_controller/metal/rendering.rb:16:in `render'
actionpack (3.1.0) lib/action_controller/metal/instrumentation.rb:40:in `block (2 levels) in render'
activesupport (3.1.0) lib/active_support/core_ext/benchmark.rb:5:in `block in ms'
/home/mike/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/1.9.1/benchmark.rb:310:in `realtime'
activesupport (3.1.0) lib/active_support/core_ext/benchmark.rb:5:in `ms'
actionpack (3.1.0) lib/action_controller/metal/instrumentation.rb:40:in `block in render'
actionpack (3.1.0) lib/action_controller/metal/instrumentation.rb:78:in `cleanup_view_runtime'
activerecord (3.1.0) lib/active_record/railties/controller_runtime.rb:24:in `cleanup_view_runtime'
actionpack (3.1.0) lib/action_controller/metal/instrumentation.rb:39:in `render'
actionpack (3.1.0) lib/action_controller/metal/implicit_render.rb:10:in `default_render'
actionpack (3.1.0) lib/action_controller/metal/implicit_render.rb:5:in `send_action'
actionpack (3.1.0) lib/abstract_controller/base.rb:167:in `process_action'
actionpack (3.1.0) lib/action_controller/metal/rendering.rb:10:in `process_action'
actionpack (3.1.0) lib/abstract_controller/callbacks.rb:18:in `block in process_action'
activesupport (3.1.0) lib/active_support/callbacks.rb:425:in `_run__4540075312289376507__process_action__207230359584297735__callbacks'
activesupport (3.1.0) lib/active_support/callbacks.rb:386:in `_run_process_action_callbacks'
activesupport (3.1.0) lib/active_support/callbacks.rb:81:in `run_callbacks'
actionpack (3.1.0) lib/abstract_controller/callbacks.rb:17:in `process_action'
actionpack (3.1.0) lib/action_controller/metal/rescue.rb:17:in `process_action'
actionpack (3.1.0) lib/action_controller/metal/instrumentation.rb:30:in `block in process_action'
activesupport (3.1.0) lib/active_support/notifications.rb:53:in `block in instrument'
activesupport (3.1.0) lib/active_support/notifications/instrumenter.rb:21:in `instrument'
activesupport (3.1.0) lib/active_support/notifications.rb:53:in `instrument'
actionpack (3.1.0) lib/action_controller/metal/instrumentation.rb:29:in `process_action'
actionpack (3.1.0) lib/action_controller/metal/params_wrapper.rb:201:in `process_action'
activerecord (3.1.0) lib/active_record/railties/controller_runtime.rb:18:in `process_action'
actionpack (3.1.0) lib/abstract_controller/base.rb:121:in `process'
actionpack (3.1.0) lib/abstract_controller/rendering.rb:45:in `process'
actionpack (3.1.0) lib/action_controller/metal.rb:193:in `dispatch'
actionpack (3.1.0) lib/action_controller/metal/rack_delegation.rb:14:in `dispatch'
actionpack (3.1.0) lib/action_controller/metal.rb:236:in `block in action'
actionpack (3.1.0) lib/action_dispatch/routing/route_set.rb:65:in `call'
actionpack (3.1.0) lib/action_dispatch/routing/route_set.rb:65:in `dispatch'
actionpack (3.1.0) lib/action_dispatch/routing/route_set.rb:29:in `call'
rack-mount (0.8.3) lib/rack/mount/route_set.rb:152:in `block in call'
rack-mount (0.8.3) lib/rack/mount/code_generation.rb:96:in `block in recognize'
rack-mount (0.8.3) lib/rack/mount/code_generation.rb:75:in `optimized_each'
rack-mount (0.8.3) lib/rack/mount/code_generation.rb:95:in `recognize'
rack-mount (0.8.3) lib/rack/mount/route_set.rb:141:in `call'
actionpack (3.1.0) lib/action_dispatch/routing/route_set.rb:531:in `call'
warden (1.1.0) lib/warden/manager.rb:35:in `block in call'
warden (1.1.0) lib/warden/manager.rb:34:in `catch'
warden (1.1.0) lib/warden/manager.rb:34:in `call'
actionpack (3.1.0) lib/action_dispatch/middleware/best_standards_support.rb:17:in `call'
rack (1.3.5) lib/rack/etag.rb:23:in `call'
rack (1.3.5) lib/rack/conditionalget.rb:25:in `call'
actionpack (3.1.0) lib/action_dispatch/middleware/head.rb:14:in `call'
actionpack (3.1.0) lib/action_dispatch/middleware/params_parser.rb:21:in `call'
actionpack (3.1.0) lib/action_dispatch/middleware/flash.rb:243:in `call'
rack (1.3.5) lib/rack/session/abstract/id.rb:195:in `context'
rack (1.3.5) lib/rack/session/abstract/id.rb:190:in `call'
actionpack (3.1.0) lib/action_dispatch/middleware/cookies.rb:326:in `call'
activerecord (3.1.0) lib/active_record/query_cache.rb:62:in `call'
activerecord (3.1.0) lib/active_record/connection_adapters/abstract/connection_pool.rb:477:in `call'
actionpack (3.1.0) lib/action_dispatch/middleware/callbacks.rb:29:in `block in call'
activesupport (3.1.0) lib/active_support/callbacks.rb:392:in `_run_call_callbacks'
activesupport (3.1.0) lib/active_support/callbacks.rb:81:in `run_callbacks'
actionpack (3.1.0) lib/action_dispatch/middleware/callbacks.rb:28:in `call'
actionpack (3.1.0) lib/action_dispatch/middleware/reloader.rb:68:in `call'
rack (1.3.5) lib/rack/sendfile.rb:101:in `call'
actionpack (3.1.0) lib/action_dispatch/middleware/remote_ip.rb:48:in `call'
actionpack (3.1.0) lib/action_dispatch/middleware/show_exceptions.rb:47:in `call'
railties (3.1.0) lib/rails/rack/logger.rb:13:in `call'
rack (1.3.5) lib/rack/methodoverride.rb:24:in `call'
rack (1.3.5) lib/rack/runtime.rb:17:in `call'
activesupport (3.1.0) lib/active_support/cache/strategy/local_cache.rb:72:in `call'
rack (1.3.5) lib/rack/lock.rb:15:in `call'
actionpack (3.1.0) lib/action_dispatch/middleware/static.rb:53:in `call'
railties (3.1.0) lib/rails/engine.rb:455:in `call'
railties (3.1.0) lib/rails/rack/content_length.rb:16:in `call'
railties (3.1.0) lib/rails/rack/log_tailer.rb:14:in `call'
rack (1.3.5) lib/rack/handler/webrick.rb:59:in `service'
/home/mike/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/1.9.1/webrick/httpserver.rb:111:in `service'
/home/mike/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/1.9.1/webrick/httpserver.rb:70:in `run'
/home/mike/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/1.9.1/webrick/server.rb:183:in `block in start_thread'

Answer 1

You're trying to use render from assets. Unfortunately, it isn't possible now, look at this .

Answer 2

You can't use Rails render. But it's possible to still use partials using Erubis::Eruby rendering directly.

$(document).ready(function() {
    $("#workout-week").append(<%= escape_javascript(
        Erubis::Eruby.new(File.read(File.join(Rails.root, 'app/views',
        '_show_training_period.html.erb'))).result(period: @period)) %>);
});

Or in Haml

$(document).ready(function() {
    $("#workout-week").append(<%= escape_javascript(
        Haml::Engine.new(File.read(File.join(Rails.root, 'app/views',
        '_show_training_period.html.haml'))).render(Object.new, period: @period)) %>);
});

For some reason using ERB breaks the sprocket rendering.
And the binding way to pass locals variables is too ugly.

It's a way around, but it's good to remember that using partials inside assets is not recommended. A better way is to place the partial code hidden somewhere in the HTML and use it in your javascripts.

Answer 3

With the new asset pipeline, inside static assets ( /app|lib|vendor/assets/ ) you can use some 'static' helpers (ie <%= asset_path "/foo/bar" %> ), because you just compile them once (if you're on production ie) and not every time you make an http req. Therefore, it makes no sense to use methods like render (or general 'dynamic' stuff) inside a static asset.

For your particular case, you could use both *.js.erb views (that will 'match' a particular action inside the controller) or javascript rendered directly inside the html.