node-alice

Node Alice

Down the rabbit hole...

A tool which renders a visualization of the call stack during the entire lifetime of a request. Showing all parent<->child relationships following any nesting. Basically it shows every line of code executed during the request, and by what.

Any parent file it does not recognise (or running in a new tick) will be placed at the top level (i.e. Express/React/react-router/Promises etc) for now.

Alice defaults to just showing the file name to give the user the option to show/hide that files executed code.

Usage

1. npm install -g node-alice
2. node-alice <entry-file>.js
3. // open your app in the browser
4. // turn the app off via <ctrl+c>
5. open alice-analyser.html

Why?

To help understand and learn (and perhaps debug) exactly what runs and from where with your application. Easily find any deep nesting and how often it is called. You can observe the code which is being run at run-time.

Of course server-side debuggers (e.g. iron-node, node debug) can show you similar information, but Alice requires no code statements or additional clicking and produces an easy to read and follow tree. You can jump straight to the area you are interested in.

Features:

• Toggle all file contents open/closed
• Filter by any file name
• Toggle filtered file name open/closed

Does your application use Babel?

As its storing exactly what code is executed, if you use a transpiler (e.g. Babel) it will show the post-compiled code.

If you used babel-node CLI you must define a .babelrc or "babel": {} block in your package.json in order for node-alice to run. Without the correct presets and plugins your app wont work (as a side-note I find it important/useful to know what my application uses from Babel anyway).

This is because node-alice uses a require-hook and babel checks up the tree for .babelrc (not down), so will not have any presets/plugins set for it. Help can be found https://babeljs.io/docs/usage/babelrc/.

Keep in mind

• Any use of iterations may print repetitive code, as it represents exactly what is run.
• Can't really be used with Webpack, the CLI command must be run against the entry js file.

Bugs

Please feel free to create an issue or email me to let me know about any bugs you discover. I would appreciate any help. Thanks

Future features:

• Add a Stats section (longest call stack, number of new ticks, worse offender).
• Web Sockets so each new request can reload the "request call stack tree" page.
• Add whitelist to recognise common parents (e.g. React/react-router/Express/Node/Promises)