position
Specifies the location in the array at which the $push operator inserts elements.
Without the $position modifier, the $push operator inserts elements to the end of the array.
A non-negative number corresponds to the position in the array, starting from the beginning of the array. If the value is greater or equal to the length of the array, the $position modifier has no effect and $push adds elements to the end of the array.
A negative number corresponds to the position in the array, counting from (but not including) the last element of the array. For example, -1 indicates the position just before the last element in the array. If you specify multiple elements in the $each array, the last added element is in the specified position from the end. If the absolute value is greater than or equal to the length of the array, the $push adds elements to the beginning of the array.
Said otherwise:
To insert elements at the end of the array, do not specify position at all.
To insert elements at the start of the array, specify
position(0).To insert elements just after the first value, specify
position(1).To insert elements just before the last value, specify
position(-1).
If this function is called multiple times, only the last value has an effect.
If this function is called without an each operator, this function does nothing.
Example
class User(
val name: String,
val scores: List<Int>,
)
collection.updateOne(
filter = {
User::name eq "Bob"
},
update = {
User::scores push {
each(50, 60, 70)
position(0) // Insert at the beginning
}
}
)