(command.CommandList
  children: [
    (C {<set>} {<-e>})
    (command.ShAssignment
      pairs: [
        (assign_pair
          lhs: (sh_lhs_expr.Name name:JS_DIR)
          op: assign_op.Equal
          rhs: {(${ Id.VSub_Name TRAVIS_BUILD_DIR) <'/js'>}
          spids: [58]
        )
      ]
    )
    (C {<pushd>} {($ Id.VSub_DollarName '$JS_DIR')})
    (C {<npm>} {<run>} {<validate>})
    (C {<popd>})
  ]
)