re-frame-10x
lets you instrument, and then inspect, the inner workings of a
running re-frame
application. It presents as a programmer's dashboard,
delivering curated insight and illumination.
It helps you to find your false assumptions faster.
re-frame
applications are computationally regular. First an event happens,
and then boom, boom, boom go a series of known computational steps (aka dominoes),
in a known order. When this chain reaction completes,
a re-frame
app enters a quiescent state waiting for another
event to kick off the next iteration of the same process.
Each re-frame
event and its consequent computation forms a bounded "epoch"
which can be inspected, analysed and understood independently of other epochs. This
tool is epoch-oriented - it shows you one at a time.
And, yes, it has "time travel debugger" capabilities - you can go
backwards and forwards through epochs - but that's really not the most interesting or powerful aspect of what re-frame-10x
delivers.
As it runs, re-frame
logs "trace" as data, and this provides an x-ray (MRI?) of your app's inner
functions. At its most basic level, re-frame-10x
is a consumer, processor and presenter
of trace data.
re-frame
is a functional framework but it's design is "data oriented". It
"flows" data, in a loop, through the functions you provide.
To understand what is happening in your re-frame
app, you must understand
what data is "happening".
So, that's two good re-frame
-specific reasons why data is at the core of
re-frame-10x
, but actually, the importance of data is even more fundamental
that that.
Each time you put a println
into your program, you are printing out what?
And why? Invariably, it is data which fuels your debugging investigation,
confirming your current hypothesis, or not.
And when you write your unit tests, you represent your expections as what? Code is proved correct by the data it produces.
So, for debugging and understanding activities, "more data, more easily" is winning. If
re-frame-10x
does its job, it shouldn't be necessary for you to add printlns
.
The data you need should be captured and presented, and, if further experimentation
is required, it should be available in your REPL too.
Perhaps you have seen LightTable in action?
In the small, it is a delightfully productive debugging environment because it co-renders code with the data generated by running the code. The data provides a "paper trail" which brings the code to life, revealing its dynamics and enriching a programmer's understanding.
re-frame-10x
has a similar goal, although the method is different.
Observing raw data trace is both interesting and valuable, but it isn't enough. First, we want to leverage this data for insights. And, second, there's often too much data - you can drown in the detail.
So, re-frame-10x
tries to be a "dashboard" which curates this
"raw data" into "information" through various kinds of analysis
and "roll ups". It should deliver insight "at a glance", while still allowing
you to drill down into the detail.
Four ways:
-
It helps you to learn
re-frame
. Simply looking at the "raw traces" provides insight into how it operates. Even experienced re-framians, er, like me, have learned a lot. -
It helps you to explore and learn an unfamiliar
re-frame
codebase. When I click, over here, on this "X" button, it shows me what event isdispatch
-ed and in which namespace the associated event handler is registered. And, "oh look, that's interesting - four subscriptions recalculated". Etc. -
It helps you with debugging. You see an x-ray of your app's functioning. In particular, it will assist you to write and debug event handlers, which is useful because they hold most of the logic in your
re-frame
apps. -
It helps you to find performance problems and/or detect where there is unnecessary computation occurring.
Point 3, is primary, of course. But Point 2 is almost as important because we all spend a lot of our time groking unfamiliar codebases. Being able to observe the inner workings of a running app is a great way to bring code to life, reveal key features, and build a cognitive map of how the code is structured.
Some of the claims above are aspirational.
re-frame-10x
remains a WIP.
Internal discussion about a name meandered for a while. Initially, it was re-frame-trace
, which is accurate, sure, but it is also 100% sausage because it talks about low level function, and not higher level benefit (sizzle, sizzle). Side stepping the issue, I wanted to call it vox-datum
(voice of the data) but that was cruelly rejected, for reasons I don't care to remember. The pain. I mean, who the hell doesn't like a Latin name?? Philistines.
If benefit was a must, then there was -insight
and -illumination
, but adding either made the name waaaay too long. Naming things - it really is a nightmare!
Finally, -10x
cheekily materialised, delivering 100 decibels of audacious sizzle, and consequently a challenge for us to live up to. A 10x programmer starts by having 10x more knowledge and insight - so go make that tool, smarty pants.
re-frame-10x configuration is per-project, only one person in your team needs to configure a project to use it, and then everyone else can benefit.
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.
- You must have a
:main
specified in your:compiler
config or an entry in:modules
(shadow-cljs) for the:preloads
and:closure-defines
to take effect - You must be running with the Closure define
goog.DEBUG
astrue
. This is the default under:optimizations :none
. - You must be using
:optimizations :none
. - You should be using re-frame 1.2.0 or later. Earlier versions may work, but are not supported.
If you don't meet those pre-requisites, see the docs on advanced setups for other ways to install re-frame-10x.
-
Update your re-frame dependency to at least
1.2.0
-[re-frame "1.2.0"]
. -
Add re-frame-10x as a dev dependency by placing
[day8.re-frame/re-frame-10x "1.6.0"]
within:dependencies
- For shadow-cljs, within
dependencies
. For example:
:dependencies [[day8.re-frame/tracing "0.6.2"] [day8.re-frame/re-frame-10x "1.6.0"]]
- For Leiningen, within
:profiles :dev :dependencies
. For example:
:profiles {:dev {:dependencies [[day8.re-frame/tracing "0.6.2"] [day8.re-frame/re-frame-10x "1.6.0"]] }}
- For deps.edn, create a new aliass, or add the dependencies in your
dev
alias:
{:aliases {:dev {:extra-deps {day8.re-frame/tracing {:mvn/version "0.6.2"} day8.re-frame/re-frame-10x {:mvn/version "1.6.0"}}}}}
- For shadow-cljs, within
-
Locate your compiler config for your development build and add
:closure-defines
and:preloads
to enable re-frame-10x.For example using shadow-cljs update your
shadow-cljs.edn
::builds {:client {:target :browser :output-dir "resources/public/js" :modules {:client {:init-fn todomvc.core/main}} :devtools {:preloads [day8.re-frame-10x.preload]} :dev {:compiler-options {:closure-defines {re-frame.trace.trace-enabled? true day8.re-frame.tracing.trace-enabled? true}}} :release {:build-options {:ns-aliases {day8.re-frame.tracing day8.re-frame.tracing-stubs}}}}}}
For example using cljsbuild and Leiningen update your
project.clj
::profiles {:dev {:cljsbuild {:builds [{:id "dev" :source-paths ["src" "dev"] :compiler {... :closure-defines {"re_frame.trace.trace_enabled_QMARK_" true} :preloads [day8.re-frame-10x.preload] :main "myapp.core" ;; You must specify a :main or follow the advanced setup ^^^ }}]}}}
If you're using figwheel-main, update your
dev.cljs.edn
file:^{:watch-dirs ["src/main/cljs"] :ring-handler "...} {:main "myapp.core" ;; You must specify a :main or follow the advanced setup ^^^ :closure-defines {"re_frame.trace.trace_enabled_QMARK_" true} :preloads [day8.re-frame-10x.preload]}
The key things you need to add are:
:closure-defines {"re_frame.trace.trace_enabled_QMARK_" true}
:preloads [day8.re-frame-10x.preload]
cljs-devtools is not required to use re-frame-10x, but it is highly recommended.
For React 18: Consider using {:preloads [day8.re-frame-10x.preload.react-18]}
. This will use React's new render API. Otherwise, expect deprecation warnings from React.
For versions < 0.4.0: If your project uses React 16 and Reagent 0.8.0-alpha2 (or higher) then you will need to add the qualifier -react16
to the version, e.g. [day8.re-frame/re-frame-10x "VERSION-react16"]
.
Note: If also using re-com then on upgrading reagent you may also need to upgrade re-com.
re-frame-10x includes an experimental code tracing feature for tracing the code in your event handlers. See day8/re-frame-debux for instructions on how to set it up.
For some settings, re-frame-10x supports project-level configuration via additional closure-defines. This way, some default behavior of 10x can be version-controlled alongside your project. Example:
{:closure-defines
{re-frame.trace.trace-enabled? true
day8.re-frame.tracing.trace-enabled? true
day8.re-frame-10x.hidden-namespaces "[com.me.uninteresting re-com.box]"}}
-
Settings which are already stored take precedence. Be sure to clear your localStorage for your project-level config to take effect.
-
Keys always begin with
day8.re-frame-10x.
-
Any value which is a collection must appear stringified, due to limitations in the closure compiler
Supported keys:
name | description | type | example |
---|---|---|---|
...history-size |
how many epochs to retain | integer | 25 |
...ignored-events |
ignore events of this type | seq of keywords | "[:init :event-B]" |
...hidden-namespaces |
hide trace from these namespaces | seq of symbols | "[re-com.box re-com.input-text]" |
...time-travel? |
selecting an event reverts your app-db | boolean | true |
...ignored-libs |
ignore low-level trace | seq of keywords | "[:reagent :re-frame]" |
...ns-aliases |
display aliased keywords in data inspectors | map of symbol->symbol | "{long-namespace ln}" |
...trace-when |
trace your app's events always, never, or only when the panel is open (default) | :panel , :always or :never |
:always |
-
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-shift-x
to slide open the trace panel and enable tracing. -
When the panel is closed, tracing is disabled.
By default, press ctrl-shift-x
to open or close the trace panel. You can re-bind or disable this keystroke in the settings menu.
You can also control the panel programmatically:
- At the REPL:
(day8.re-frame-10x/show-panel! true)
- At the browser console:
day8.re_frame_10x.show_panel_BANG_(true)
- With a re-frame event:
(re-frame.core/dispatch [:day8.re-frame-10x.panels.settings.events/show-panel? true])
- Inspect a portion of app-db's state with the path inspector, allowing you to focus on just the parts you care about.
- Reset app-db to before an event was run to run it again, instead of resetting the whole application
- Toggle app-db before and after states for running an event, to inspect UI changes.
- See the output and diff of a subscription running
- Spot layer 2 subscriptions that should really be layer 3's.
- Spot subscriptions that are running when they shouldn't
- Spot subscriptions that are being destroyed and recreated unnecessarily
- Answer the question "Why is my app slow when it runs this event?"
- See whether time is spent in processing an event, running the subscriptions, or rendering the changes
- See the coeffects given to an event handler
- See the effects produced by an event handler
- See the interceptors involved in handling an event.
- Dig into the low level execution details of an epoch. We've tried to surface the useful information in the other panels, so if you're constantly referring to this panel, open an issue with your use case.
- Try a
lein clean
- Make sure you have followed all the installation steps.
- Make sure you have checked the prerequisites
re-frame-10x persists its state in local storage. If you experience a bug, this mechanism may be reproducing your bug, even after the root cause is fixed. To fully refresh the state:
- Click "Factory Reset" at the bottom of the settings panel.
- If you can't load the settings panel, run
day8.re_frame_10x.factory_reset_BANG_()
in the JavaScript console. - If neither of those work, remove all of the keys with the prefix
day8.re-frame.trace
.
- Make sure that your browser window doesn't have focus in a text-box or something else that is intercepting keyboard events.
- Make sure that the re-frame-10x div has been created. Run
document.querySelector('#--re-frame-10x--')
in your browser's console to check if an element is returned. If this returnsnull
then something else isn't working correctly. - Try a factory reset. This should restore the default key bindings.
- You can also open it programmatically.
- Try a factory reset
- Make sure you are using the minimum recommended re-frame version in the prerequisistes. Some parts of re-frame-10x rely on updated versions of re-frame to capture the information it needs.
- Make sure your original browser window is open to the tab where your app is running. If you need other tabs, consider visiting them in a different window.
- In other words, keeping your app in a single browser window with no other tabs should always work.
- This is due to a limitation built into modern browsers. We discuss it in depth at #209.
- In rare cases, a factory reset may help.
re-frame is instrumented - all important activity generates trace data.
re-frame-10x
consumes this trace data and renders useful visualisations of the re-frame
process. Currently, re-frame's tracing capabilities are in alpha and are subject to change at any time. We're testing the utility of the the trace by building an app on top.
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-10x.preload]
) has to be set in order to automatically monkeypatch Reagent to add appropriate lifecycle hooks. Yes this is gross, and yes we will 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.
If you want to work on re-frame-10x, see DEVELOPERS.md.
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