How to declare mapping for nested fields in Elasticsearch to allow for storing different types? - elasticsearch

Question

In essence, I want my mapping to be as schemaless as possible, but allow for nested types and being able to store data that may have different types:
When I try to add a document where some fields have different types of values, I get an error like this:
"type": "illegal_argument_exception",
"reason": "mapper [data.customData.value] of different type, current_type [long], merged_type [text]"
This can easily be solved by mapping the field value to text (or create it dynamically by first inserting a document with only text). However, I would like to avoid having a schema. Perhaps having all of the fields nested in customData to be set to text? How do I do that?
I had the problem earlier, but then it started working after accidentally managing to get a dynamical mapping that worked (since everything was regarded as text. I was later made aware of this problem since I needed to change the mapping to allow for nested types.
Documents with this kind of data are troublesome to store successfully:
"customData": [
{
"value": "some_text",
"key": "some_text"
},
{
"value": 0,
"key": "some_text"
}
]
A part of the mapping that works:
{
"my_index": {
"aliases": {},
"mappings": {
"_doc": {
"properties": {
"data": {
"properties": {
"customData": {
"properties": {
"key": {
"type": "text",
"fields": {
"keyword": {
"type": "keyword",
"ignore_above": 256
}
}
},
"value": {
"type": "text",
"fields": {
"keyword": {
"type": "keyword",
"ignore_above": 256
}
}
}
}
}
}
},
"some_list": {
"type": "nested",
"properties": {
"some_field": {
"type": "text",
"fields": {
"keyword": {
"type": "keyword",
"ignore_above": 256
}
}
}
}
}
}
}
}
}
}
In essence, I want the mapping to be as schemaless as possible, but allow for nested types and being able to store data that may have different types:
{
"mappings": {
"_doc": {
"properties": {
"data": {
"type": "object"
},
"somee_list": {
"type": "nested"
}
}
}
}
}
So what would be the best approach to go about this problem?