re-frame-10x/README.md

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re-frame-trace

A trace panel for re-frame.

Clojars Project

Status: Alpha.

Motivation

re-frame provides a data driven architecture, but we need to be able to inspect it. re-frame-trace takes inspiration from redux-devtools, and provides several ways to visualise the structure and state of your re-frame application.

Installation

If you are using leiningen, modify project.clj in the following ways. When puzzling over the various possible leiningen configurations, it's often helpful to look at a sample project.clj.

Clojars Project

  • Add re-frame-trace as a dev dependency by placing [day8.re-frame/trace "VERSION"] within :profiles :dev :dependencies. For example:

    :profiles
       {:dev
          {:dependencies [[some-other-package  "0.0.0"]
                          [day8.re-frame/trace "0.1.7"]] }}
    
  • Locate the :compiler map under :dev and add:

    • :closure-defines {"re_frame.trace.trace_enabled_QMARK_" true}
    • :preloads [day8.re-frame.trace.preload]

    For example:

    {:builds
       [{:id           "dev"
         :source-paths ["src" "dev"]
         :compiler     {...
                        :closure-defines      {"re_frame.trace.trace_enabled_QMARK_" true}
                        :preloads             [day8.re-frame.trace.preload]}}]}
    

cljs-devtools is not required to use re-frame-trace, but it is highly recommended.

Usage

  • Make sure you have followed all of the installation instructions above.

  • Start up your application.

  • Once it is loaded, focus the document window and press ctrl-h to slide open the trace panel and enable tracing.

  • When the panel is closed, tracing is disabled.

Troubleshooting

  • Try a lein clean
  • Make sure you have followed all the installation steps.

How does it work?

re-frame has instrumentation to collect traces throughout various important points in the lifecycle of a re-frame app. re-frame-trace is a consumer of these traces, and provides visualisations of the traces. These traces have a well-defined structure, and will eventually be standardised, allowing other developers to create their own tooling to work against the traces. Currently, re-frame's tracing and re-frame-trace are in alpha and are subject to change at any time.

By default, re-frame tracing is compiled out, so it won't impose a performance cost in production. The trade-off here is that you need to explicitly enable it in development.

The preloads option (:preloads [day8.re-frame.trace.preload]) has to be set in order to automatically monkeypatch Reagent to add appropriate lifecycle hooks. Yes this is gross, and yes we will try and make a PR to reagent to add proper hooks, once we know exactly what we need. The preload namespace also injects a div containing the devtools panel into the DOM.

Developing/Contributing

If you want to work on re-frame-trace, see DEVELOPERS.md.