gval VS goja

For practical start, see this: https://www.youtube.com/watch?v=JiViND-bpmw It explain one particular type of parser type that is quite easy to grasp and fun to write. Also look on some libraries that deliver "expression executors" - these are in fact small interpreted languages and can give you plenty of examples. Classic one (though currently unmaintaines I think) is: https://github.com/PaesslerAG/gval but there are plenty more, just google for them. On my last words, this is very enjoyable part of programming but it requires much learning so be patient and have fun!

There is a nice lib that let you write much more compact expressions https://github.com/PaesslerAG/gval I'm using this lib for evaluating expressions in a small BPMN engine. At least your solution is missing a context, functions and data to work on. But trying stuff out is propably the best way to learm Go!

dop251/goja

Your comment was posted 4 minutes ago. That means you still have enough time to edit your comment to change it so it contains real URLs:

<https://github.com/PuerkitoBio/goquery>

<https://github.com/dop251/goja>

(Please do not reply to this comment—I won't be able to delete it once the previous post is fixed if it contains replies.)

Apparently "not depending on Node or V8" means depending on some random Go JS engine instead.

Goja https://github.com/dop251/goja

Either call a JavaScript interpreter like node with exec.Command and read its stdout, or use a pure Go JavaScript interpreter like goja or otto.

Just to also say this is implemented in pure Go we aren't including V8 or any external dependencies we instead use https://github.com/dop251/goja which is a JS VM written completely in Go.

If you want to serialize a function to JSON one idea may be to embed a scripting language like JavaScript into your program. The goja package is a very good solution: a native ES5 JavaScript (with some ES6 syntax support as well) natively implemented in Go so you can get tight data bindings to your Go types and funcs. For your JSON marshalling you could serialize a JavaScript function source (text) and when reloading that, parse that text with goja to be able to run it dynamically in your Go program. Basically you'd need to get away from pure Go for this and towards something that is JSON compatible to (de)serialize to text.

Not really. It was built in-house and I don't know of anything about it that went public. I recall it using Goja for the JS runtime. Code was embedded into the binary (think embed package). There was some kind of sorcery to convert what would be HTTP network calls in the browser into local function calls during SSR, but I'm hazy on how it worked I'm afraid.