Thirty seconds. Keep shipping.

function·collectActiveUsers(users,·cutoff)·{
··const·activeUsers·=·[]

··for·(const·user·of·users)·{
····if·(!user.isOnline·||·user.lastSeenAt·<=·cutoff)·{
······continue
····}

····activeUsers.push(user.name)
··}

··return·activeUsers
}

function·groupPostsByTag(posts)·{
··const·grouped·=·{}

··for·(const·post·of·posts)·{
····for·(const·tag·of·post.tags)·{
······grouped[tag]·??=·[]
······grouped[tag].push(post.slug)
····}
··}

··return·grouped
}

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