Use jq to collect recursive-descent results into a single array

Is it possible to collect recursive-descent results into a single array with jq?

Would flatten help? Looks so to me, but I just cannot get it working. Take a look how far I am now at https://jqplay.org/s/6bxD-Wq0QE, anyone can make it working?

BTW,

.data.search.edges[].node | {name, topics: ..|.topics?} works, but I want all topics from the same node to be in one array, instead of having same name in all different returned results.
flatten alone will give me Cannot iterate over null, and
that's why I'm trying to use map(select(.? != null)) to filter the nulls out. However, I'd get Cannot iterate over null as well for my map-select.

So now it all comes down to how to filter out those nulls?

UPDATE:, by "collect into a single array" I meant to get something like this:

[
  {
    "name": "leumi-leumicard-bank-data-scraper",
    "topics": ["banking", "leumi", "api", "puppeteer", "scraper", "open-api"]
  }
]

instead of having same name duplicated in all different returned results. Thus recursively descends seems to me to be the option, but I'm open to any solution as long as I can get result like above. Is that possible? Thx.

Solution

One way to collect the non-falsey values:

.data.search.edges[].node 
| {name, topics: [.. | .topics? | select(.)]}

The result would be:

{
  "name": "leumi-leumicard-bank-data-scraper",
  "topics": [
    "banking",
    "leumi",
    "api",
    "puppeteer",
    "scraper",
    "open-api"
  ]
}
{
  "name": "echarts-scrappeteer",
  "topics": []
}