Using flow installed under node_modules in lsp-mode

my-lsp-search-node_modules.el

(with-eval-after-load 'lsp
  (defun my-lsp-search-node_modules ()
    (and buffer-file-name
         (lsp-clients-flow-activate-p buffer-file-name major-mode)
         (let* ((flow-location "node_modules/.bin/flow")
                (root (locate-dominating-file buffer-file-name flow-location)))
           (if root
               (set (make-local-variable 'lsp-clients-flow-server)
                    (expand-file-name flow-location root))))))

  (add-hook 'lsp-mode-hook #'my-lsp-search-node_modules))