How to access a return value from a node script in BASH?

Let’s say I have a bash script that calls a node script. I’ve tried to do it like this:

b.sh file:

#!/bin/bash
v=$(node app.js)
echo "$v"

app.js file:

#!/usr/bin/env node
function f() {
   return "test";
}
return f();

How do I access the value returned by the node script (“test”) from my bash script ?

Answer

@Daniel Lizik gave an good answer (now deleted) for the part: how to output the value, e.g. using his answer:

#!/usr/bin/env node
function f() {
   return "test";
}
console.log(f())

And for the part how to capture the value in bash, do exactly as in your question:

#!/bin/bash
val=$(node app.js)
echo "node returned: $val"

the above prints:

node returned: test