I can create a type for an array of N element of string type:
type A = string[];
as well as a predefined number of elements, such as exactly 2 elements:
type A = [string, string];
What I am trying to have is a type that will accept 2 or more elements, but not just one or none.
type A = ?
A = ['a', 'b']; // OK
A = ['a', 'b', 'c']; // OK
A = ['a', 'b', ... 'N']; // OK
A = ['a']; // Error
A = []; // Error
Is this possible?
CodePudding user response：
You can use rest elements in tuple types to indicate that the tuple type is open-ended and may have zero or more additional elements of the array element type:
type A = [string, string, ...string[]];
The type A must start with two string elements and then it can have any number of string elements after that:
let a: A;
a = ['a', 'b']; // OK
a = ['a', 'b', 'c']; // OK
a = ['a', 'b', 'c', 'd', 'e', 'N']; // OK
a = ['a']; // error! Source has 1 element(s) but target requires 2
a = []; // error! Source has 0 element(s) but target requires 2.