How to call `var iris = console.r.get("iris");` from node JS?

[emmansh]

I've just found this V8 library and am trying to wrap my head around it. I want to call R from node JS script. How should I do it?

I've tried to first open R and typed:

library(V8)
ctx <- v8()
ctx$console()

Then, I opened a separate text editor and wrote a simple js command

// in js
var iris = console.r.get("iris");
console.log(iris)

Then ran the script with node, and got:

var iris = console.r.get("iris");
^

TypeError: Cannot read properties of undefined (reading 'get')
at Object.

Clearly, I'm missing something fundamental. How can I call iris from node.js?

I read the vignettes (especially the Callback to R part) and googled around but couldn't figure this out. Any help would be appreciated!

[jeroen]

V8 in R is not connected to nodejs. The idea of that example is you paste that javascript code in the R temrinal, in the ctx$console() that you just opened.

Or in a scripted way you can do:

library(V8)
ctx <- v8()
# Evaluate some javascript
ctx$eval("var foo = 123 + 456")
ctx$get("foo")

# Call R in JavaScript
script <- 'var iris = console.r.get("iris");
var x = iris[1];
console.log(x)'
ctx$eval(script)
ctx$get("x")

[emmansh]

Snap, this is the answer I was afraid of. Could you point to a technique/method/framework that enables to call R from node js?

[jeroen]

If you run both on the same machine, you need an npm package that calls R. Maybe this one? https://www.npmjs.com/package/r-integration

If your R is running on a remote server, you could try something like opencpu or similar: https://www.npmjs.com/package/opencpu

[emmansh]

Thanks. Yeah I've seen r-integration but the problem is: calling R from node means it runs Rscript and parses the console print back into node. Which is hacky and prone to error. I'm looking for a more solid solution. v8 indeed seemed too good to be true.