pdjs: JavaScript for PD
Hey, I've made pdjs, an external that executes JavaScript using V8 and tries to emulate Max's js object.
It lives at https://github.com/mganss/pdjs and is available through deken for x64-windows, x64-linux, and arm64-linux currently (x64-macos planned).
Most core functionality is there so a lot of code written for Max js that doesn't use any extra objects (like LiveAPI, Buffer, Dict, etc.) should run unchanged.
Please report any issues or missing features at GitHub.
@tabache You can find a few patches in the test-* directories of the pdjs repo here: https://github.com/mganss/pdjs/tree/master/test
These are part of the automated tests for pdjs so don't reflect real use cases but might be helpful to get a feel for how pdjs can be used. You'll probably need to add [declare -path pdjs] if pdjs isn't in PD's default search paths.
@lacuna Thanks. Here's a nice HOWTO about writing externals for PD: https://github.com/pure-data/externals-howto
Documentation about embedding V8 can be found here: https://v8.dev/docs/embed
@mganss @jancsika Following some ideas from this thread, i made a simple wrapper for pdjs, with which you can write javascript code directly into objects. It is not very pretty and you have to use [] instead of {}, but it is some fun:
As the script file is rewritten and the code compiled each time the wrapper is called, this could also work as an extension, where javascript.pd and script are within an extension folder and can be called from everywhere. 
This is just experimental and an early idea. No idea if this could go somewhere.
@ingox Very nice! Perhaps pdjs could be extended by allowing script to be provided in the [js] object's arguments, thereby circumventing the requirement for a script file.
Max has the ability to edit the script using an internal editor. Is there a way to provide something similar in PD? Perhaps using a separate editor object and passing the text to pdjs via a message?
@mganss It would be possible to open a [text] from click. Problem is that Pd freezes if curly brackets are inserted into [text] and saved. The impulse would be to copy/paste Javascript code into the [text] and that would be dangerous... 
@ingox it is possible to use curly brackets in the "textwindow" from ofelia, but no idea how to implement that in another external...
That's great!
For characters limitation in GUI, like curly braces, there was a PR on the road
https://github.com/pure-data/pure-data/pull/953
Fantastic work! I've been working with pyext and pdlua before, but still most proficient with js 
Regarding having an editor inside PD - perhaps the underused Tcl/Tk GUI plugins could come in help with this, will look into this!
will try to add maybe simple REPLish input first, some examples of the possibilities:
https://puredata.info/docs/guiplugins/GUIPlugins/
https://github.com/pd-externals/tclprompt-plugin
https://forum.pdpatchrepo.info/topic/9960/tcl-for-a-rainy-day
@eeropic FWIW here are two more things I'd love to have:
Autowatch. Here's a small cross platform solution: https://github.com/FigBug/Gin/blob/master/modules/gin/utilities/gin_filesystemwatcher.cpp
Chrome Developer Tools integration (debugging): https://hyperandroid.com/2020/02/12/v8-inspector-from-an-embedder-standpoint/
Not sure if this would allow debugging from VS Code as well.
I wrote a patch to document a little pdjs external in:
https://forum.pdpatchrepo.info/topic/13510/modules-in-pdjs/4
Open to contributions.
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