why not just function baz(modifier) { let foo = do_a(); let bar = modifier(foo); return do_b(bar); } Example 1: baz((foo) =>

why not just function baz(modifier) { let foo = do_a(); let bar = modifier(foo); return do_b(bar); } Example 1: baz((foo) => foo); Example 2: baz((foo) => do_z(foo)); Example 3: baz((foo) => foo + 10); which lets you be more concise with baz = (modifier) => do_b(modifier(do_a()))