Сreating multilevel json with the jq utility in a bash script

I get the contents of a text file into an array and then sequentially get the elements of the array and try to add the elements to the json:

#!/bin/bashJSON=$(jq -n '')readarray -t array < ./station.samplecount=0for e in "${array[@]}"do    if echo "$e" | grep -Eq '^[0-9]{10}'>/dev/null      then        timestamp=$e        datetime=`date +'%Y-%m-%d %H:%M:%S' -d "@$e"`        JSON=$(echo $JSON | jq --arg timestamp "${timestamp}" '. += $ARGS.named')        JSON=$(echo $JSON | jq --arg datetime "${datetime}" '. += $ARGS.named')    fi    if echo "$e" | grep '^Station '>/dev/null      then        NODE=$(jq -n '')        mac=`echo "$e" | awk '{ print $2 }'`        interface=`echo "$e" | awk '{ print $4 }' | rev | cut -c2- | rev`        JSON=$(echo $JSON | jq --argjson nodes "[]" '. += $ARGS.named')        JSON=$(echo $JSON | jq --arg mac "${mac}" --arg count "${count}" '.nodes[0] += {"mac": $mac}')    JSON=$(echo $JSON | jq --arg interface "${interface}" '.nodes[0] += {"interface": $interface}')        count=$((count+1))    fidone

As a result, I get a json like this:

{"timestamp": "1721396365","datetime": "2024-07-19 16:39:25","nodes": [    {"mac": "14:88:00:00:00:06"    }  ]}

But I need to add multiple objects to the list, so I set a count variable and want to use it to specify the index of the list:

JSON=$(echo $JSON | jq --arg mac "${mac}" --arg count "${count}" '.nodes[$count] += {"mac": $mac}')

But in this variant adding list items doesn't work.

How can I dynamically specify the index of the list?

I've tried all the options that came to mind, but I haven't found a solution yet:

 NODE=$(echo $NODE | jq --arg mac "$mac" '. += $ARGS.named') NODE=$(echo $NODE | jq --arg interface "${interface}" '. += $ARGS.named') JSON=$(echo $JSON | jq --argjson node "${NODE}" '.nodes[.nodes | length] = $ARGS.named')

It is necessary to use a variable to specify the index of the list.