打印数组中的JSON值，并且此数组在另一个数组中

Question

Maybe this problem is duplicated, but I don't find an answer that respond my problem.

I am trying to access to a value in JSON, but this is in array, and that is inside another array. This is the example:

Original JSON:

{"object":"page","entry":
[{"id":"488064221540488","time":1501681094769,"messaging":[{"sender":
{"id":"1559711167437676"},"recipient":
{"id":"488064221540488"},"timestamp":1501681094579,"message":
{"mid":"mid.$cAAHhEUCp_UVj1HBXs1do8-
BMiIPg","seq":559,"text":"Thunder."}}]}]}

I am trying to access to value of sender key:

...[{"sender": {"id: "1559711167437676"}, ...

I am trying access via properties of the original request, but I get undefined. I am trying like this.

console.log(JSON.stringify(req.body.entry.messaging))    // At this point, I get undefined

I've tried with JSON.parser but the same result is thrown. This is only one of multiple statement that I've used to get the result.

Someone can help me to print this exact value, you can see that is inside of array that is inside of another array, this sound complex, but I don't know. Hope you can help me.

Answer 1

entry is an array (take note of the square brackets), so you need to at least reference the index you are interested in. The same is true for messageing , so get to the id like this:

req.body.entry[0].messaging[0].sender.id

 const req = { body: { "object": "page", "entry": [{ "id": "488064221540488", "time": 1501681094769, "messaging": [{ "sender": { "id": "1559711167437676" }, "recipient": { "id": "488064221540488" }, "timestamp": 1501681094579, "message": { "mid": "mid.$cAAHhEUCp_UVj1HBXs1do8-BMiIPg", "seq": 559, "text": "Thunder." } }] }] } }; const id = req.body.entry[0].messaging[0].sender.id; console.log(id, parseInt(id));