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(); Some functions require you to pass in bytecode to the function. The type of the bytecode parameter is usually Vec<u8>, here's an example of how to pass bytecode to a function:
fn compute_bytecode_root(bytecode_input: Vec<u8>) -> b256 {
//simply return a fixed b256 value created from a hexadecimal string from testing purposes
return 0x0102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f20;
} To pass bytecode to this function, you can make use of the arrayify function to convert the bytecode file contents into a UInt8Array, the TS compatible type for Sway's Vec<u8> type and pass it the function like so:
// #import { arrayify, readFile };
const bytecode = await readFile(bytecodePath);
const bytecodeAsVecU8 = arrayify(bytecode);
const { value: bytecodeRoot } = await bytecodeContract.functions
.compute_bytecode_root(bytecodeAsVecU8)
.call();