Function landing_is_nested 

pub fn landing_is_nested(
    layout: &InvocationLayout,
    environment: &[(OsString, OsString)],
) -> bool

What: Whether this invocation lands under an ancestor’s landing lock. Why: The ancestor’s lock is the one the reservation holder waits for, so a nested landing neither waits nor reserves.

In TS you’d write (pseudocode):

await hasValidLandingLease({ environment: process.env, lockDirectory })