kotlin-stdlib / kotlin.collections / AbstractMutableList / addAll addAll Common 1.0 open fun addAll(elements: Collection<E>): Boolean(source) Common JS 1.0 open fun addAll(index: Int, elements: Collection<E>): Boolean(Common source) (JS source) Inserts all of the elements of the specified collection elements into this list at the specified index. Return true if the list was changed as the result of the operation.