Instructions

This is a very specific tool designed to take two source maps and map a position in react native bundled js back to cljs source code. It helped us find a specific production bug at a specific time, when using the sentry error tracker - your mileage may vary...

To build the js script

shadow-cljs release script

To run the js script

node sourcemap.js <options>

Options

Required:

• --js sourcemap to advance compiled js <path/to/js.map>
• --cljs sourcemap to clojurescript <path/to/cljs.map>

Optional:

• --locations comma separated list of locations e.g. 11:90000, 11: 20000
• --stacktrace stacktrace copied from sentry <path/to/stacktrace.txt>
• --match filter only sources containing text e.g. some-ns

Basic use

Where main.ios.map is the sourcemap that maps from the final bundled js to the advanced compiled js, and index.js.map is the sourcemap that maps from the advanced compiled js to the original cljs.

You can get main.ios.map from e.g. expo's post publish hook (see using expo with sentry in the expo docs), and index.js.map will be output by shadow-cljs into the target directory alongside index.js, so long as :compiler-options {:sourcemap true} is set in shadow-cljs.edn.

1. Download main.ios.map and index.js.map from e.g. sentry
2. Run node sourcemap.js --js ~/Downloads/main.ios.map --cljs ~/Downloads/index.js.map --locations 11:90000

Typical process (with stacktrace)

Follow step 1 as above, but then copy the stacktrace string into a file. Stacktrace will be parsed for <line>:<column> pairs.

app:///main.ios.bundle at line 11:935705
app:///main.ios.bundle in Mf at line 11:28521
app:///main.ios.bundle in D at line 11:31231
app:///main.ios.bundle in e at line 11:61222
app:///main.ios.bundle in u at line 11:61158
app:///main.ios.bundle in vw at line 11:149747
...

1. pbpaste > stacktrace.txt
2. node sourcemap.js --js ~/Downloads/main.ios.map --cljs ~/Downloads/index.js.map --stacktrace stacktrace.txt

Which should give an output like the following - which is not pretty, but hopefully enough to avoid despair:

11:935705
{:source riverford/mobile_app_orders/util.cljs, :line 222, :column 80, :name s}
11:28521
{:source cljs/core.cljs, :line 3901, :column 18, :name a0}
11:31231
{:source cljs/core.cljs, :line 3931, :column 29, :name args}
11:61222
{:source cljs/core.cljs, :line 10789, :column 29, :name args}
11:61158
{:source cljs/core.cljs, :line 10786, :column 11, :name args}
11:149747
{:source riverford/mobile_app_orders/util.cljs, :line 599, :column 56, :name t}
11:420016
{:source riverford/mobile_app_orders/subs/your_account.cljs, :line 74, :column 76, :name me}