I feel uneasy about it. Eusebius is clear, that the criterion between canonical and non canonical (but otherwise orthodox) books is weather it was written by eyewitnesses or under the supervision of eyewitnesses – or not.
Supposing that the Didache, and together with that the Gospel of Thomas was written early, weakens this criterion, as much as the supposition that all Gospels were written after the destruction of the Temple.
It is estimated to have been written around 70AD to 100AD and could be construed as an early Catechism.
Even in the current Catechism of the Catholic Church references are made to The Didache.
DISCLAIMER: Catholic Answers has turned over the archive to Catholic-Questions.org and no longer owns, manages, or moderates the forums. For additional apologetics resources please visit www.catholic.com.