re-frame-10x/README.md

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# re-frame-trace
A trace window for re-frame
## 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](https://github.com/gaearon/redux-devtools), and provides several ways to visualise the structure and state of your re-frame application.
<img src="docs/images/trace-window.png" height="400px">
## 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. Caveat usor [sic].
## Getting started
Compile your app with `:closure-defines: "re_frame.trace.trace_enabled_QMARK_" true` and `:preloads [day8.re-frame.trace.preload]`, e.g.
```cljs
{:builds
[{:id "dev"
:source-paths ["src" "dev"]
:compiler {...
:closure-defines {"re_frame.trace.trace_enabled_QMARK_" true}
:preloads [day8.re-frame.trace.preload]}}]}
```
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](https://github.com/clojure/clojurescript/wiki/Compiler-Options#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.
Now you can start up your application. Once it is loaded, press Ctrl+H to slide open the trace panel and enable tracing. When the panel is closed, tracing is disabled.