skip yarn add if installed, but allow yarn upgrade if set in local_vars

roles/internetarchive/defaults/main.yml

@@ -7,3 +7,4 @@
 # If nec, change them by editing /etc/iiab/local_vars.yml prior to installing!
 
 internetarchive_dir: '{{ iiab_base }}/internetarchive'
+IA_upgrade: False

roles/internetarchive/tasks/main.yml

@@ -22,7 +22,9 @@
   command: sudo yarn add @internetarchive/dweb-archive @internetarchive/dweb-mirror
   args:
     chdir: "{{ internetarchive_dir }}"
+    creates: "{{ internetarchive_dir }}/node_modules/@internetarchive/dweb-mirror/internetarchive"
   when: internet_available | bool
+  register: IA_installing
 
 - name: Create directory /library/archiveorg
   file:
@@ -30,6 +32,12 @@
     state: directory
     owner: "root"
 
+- name: Update pre-existing install
+  command: sudo yarn upgrade
+  args:
+    chdir: "{{ internetarchive_dir }}"
+  when: not IA_installing.changed and IA_upgrade
+
 
 # CONFIG FILES