Navigate to previous commit

When one commit comes before another in a sequence, it can be referred to as its parent:

A commit object may have any number of parents. With exactly one parent, it is an ordinary commit. Having more than one parent makes the commit a merge between several lines of history.

Initial (root) commits have no parents

When viewing the initial commit, the commit won’t have a parent.

To account for this, guard the render block with a presence checking conditional.