Creates a list of the given length.
The created list is fixed-length if length is provided.
List fixedLengthList = new List(3);
fixedLengthList.length; // 3
fixedLengthList.length = 1; // Error
The list has length 0 and is growable if length is omitted.
List growableList = new List();
growableList.length; // 0;
growableList.length = 3;
To create a growable list with a given length, just assign the length right after creation:
List growableList = new List()..length = 500;
The length must not be negative or null, if it is provided.
Source
external factory List([int length]);