Append to array in Elasticsearch - elasticsearch

Question

I am currently struggling a bit on how to append a value to an array in elasticsearch.
The Document looks something like this:
{
"took": 11,
"timed_out": false,
"_shards": {
"total": 5,
"successful": 5,
"failed": 0
},
"hits": {
"total": 1,
"max_score": 1,
"hits": [
{
"_index": "iethreads",
"_type": "thread",
"_id": "AVRk6WRMU5h_y_zwo4s0",
"_score": 1,
"fields": {
"links": [
"[\"https://somelink123.net/thread-714222&page=1\", \"https://somelink123.net/thread-714222&page=2\", \"https://somelink123.net/thread-714222&page=3\", \"https://somelink123.net/thread-714222&page=4\"]"
]
}
}
]
}
}
then I run the following update query
POST _update
{
"script" : "ctx._source.links+=new_posts",
"params" : {
"new_posts":"blabliblub"
}
}
and I get this:
{
"took": 11,
"timed_out": false,
"_shards": {
"total": 5,
"successful": 5,
"failed": 0
},
"hits": {
"total": 1,
"max_score": 1,
"hits": [
{
"_index": "iethreads",
"_type": "thread",
"_id": "AVRk6WRMU5h_y_zwo4s0",
"_score": 1,
"fields": {
"links": [
"[\"https://somelink123.net/thread-714222&page=1\", \"https://somelink123.net/thread-714222&page=2\", \"https://somelink123.net/thread-714222&page=3\", \"https://somelink123.net/thread-714222&page=4\"]blabliblub"
]
}
}
]
}
}
So for me this looks like the array is treated like a string and it just appends the string - this is not what I want.
How would I append the "blabliblub" as a new element to the array ?

Answer 1

It seems your links field actually has one element as string instead of an array. To your update be succesful, your structure must be like that:
"fields": {
"links": [
"https://somelink123.net/thread-714222&page=1",
"https://somelink123.net/thread-714222&page=2",
"https://somelink123.net/thread-714222&page=3",
"https://somelink123.net/thread-714222&page=4"
]
}