How to convert a string that represents a time in order to use it in time calculations?
jq -c '.[]|strptime("%H:%M")' tmp/start-end-times.json
jq -c '.[0]|strptime("%H:%M")' tmp/start-end-times.json
jq -c '[.[]|strptime("%H:%M")]' tmp/start-end-times.json
jq -c 'map(strptime("%H:%M"))' tmp/start-end-times.json # <- the same as above!