Array.isArray(xi): true
xi.length: 3
xi[1]: 1
post update -- xi[1]: 5
post update -- xi.length: 4
post update -- xi[3]: 10
post update -- xi[5]: undefined
Array.isArray(xd): true
xd.length: 3
xd[1]: 1.5
post update -- xd[1]: 5
post update -- xd.length: 11
post update -- xd[3]: 10
post update -- xd[5]: undefined
post update -- xd[10]: 10