Support access to attribute name to use it as value in projections

[Vitalhead]

There are many cases when you need to convert an attribute name into values. What ma help is to have a keys() function that returns an array of keys.

Use Case 1:
Objects described in Json where ID of the object is the key need to be converted into an array of objects where ID is the property.
For example:
{
“a”: {"prop": "value1"},
“b”: {"prop": "value2"}
}
Convert to:
[
{“_id”: “a”, "prop": "value1"},
{“_id”: “b”, "prop": "value2"}
]

Use Case 2:
Key-value pairs need to be expanded to objects. And it should work for the arbitrary number of attributes.
For example:
{
“name”: "Milk",
“price”: 1
}
Convert to:
[
{“prop”: “name”, "value": "Milk"},
{“prop”: “price”, "value": 1}
]

[judofyr]

Just brainstorming some ideas here:

What about a function called entries(…) which turns an object{"a": "c"} into [{"key": "a", "value": "c"}? Your two examples would then be entries(foo) | { "_id": key, ...value } and entries(foo) | { "prop": key, value }.

[Vitalhead]

entries() function may work. How it will behave on array?

Also, need to think if it will help in the following use case:
[ [col1, col2], [val11, val12], [val21, val22] ]
to convert to:
[ {col1: val11, col2: val12}, {col1: val11, col2: val12}, ]