surf js never returns expression values

[SeMmyT]

Problem

surf js "expression" always prints "undefined" regardless of the expression. Even simple literals like surf js "1 + 1" return "undefined".

Root cause: The EXECUTE_JAVASCRIPT handler wraps user code in (async () => { 'use strict'; <code> })(). This async IIFE never returns a value because there's no return statement for the last expression.

Current workaround

surf js 'console.log("RESULT:" + document.cookie)'
surf console | grep RESULT

Proposed fix

Auto-detect single expressions and add return to make them evaluate like a REPL. Multi-statement code continues to work as-is.

# Should work:
$ surf js "1 + 1"
2

$ surf js "document.title"
"My Page Title"

$ surf js "document.querySelectorAll('button').length"
3

Severity

High — forces workarounds on every JS evaluation in AI agent workflows.