In Sway, a Vector is a dynamic-sized collection of elements of the same type. Vectors can hold arbitrary types, including non-primitive types.
A basic Vector in Sway is similar to a TypeScript Array:
// Sway Vec<u8>
const basicU8Vector = [1, 2, 3]; Consider the following example of a EmployeeData struct in Sway:
pub struct EmployeeData {
name: str[8],
age: u8,
salary: u64,
idHash: b256,
ratings: [u8; 3],
isActive: bool,
} Now, let's look at the following contract method. It receives a Vector of the Transaction struct type as a parameter and returns the last Transaction entry from the Vector:
fn echo_last_employee_data(employee_data_vector: Vec<EmployeeData>) -> EmployeeData {
employee_data_vector.get(employee_data_vector.len() - 1).unwrap()
} The code snippet below demonstrates how to call this Sway contract method, which accepts a Vec<Transaction>:
// #import { getRandomB256 };
const employees = [
{
name: 'John Doe',
age: 30,
salary: 8000,
idHash: getRandomB256(),
ratings: [1, 2, 3],
isActive: true,
},
{
name: 'Everyman',
age: 31,
salary: 9000,
idHash: getRandomB256(),
ratings: [5, 6, 7],
isActive: true,
},
];
const { value } = await contract.functions.echo_last_employee_data(employees).simulate();Currently, returning vectors is not supported by Sway. If you try returning a type that is or contains a Vector, you will get a compile-time error.