Write Solana programs
in TypeScript.

1import { type Account, type Init, type Mut, type Pubkey, type Signer, type SystemProgram, type u8, type u64, require } from "typesol";2 3export interface Counter {4  authority: Pubkey;5  count: u64;6  bump: u8;7}8 9export enum CounterError {10  Unauthorized = "Only the counter's authority can change it",11}12 13/** Create the caller's counter at PDA ["counter", authority]. */14export function initialize(authority: Mut<Signer>, counter: Init<Counter>, systemProgram: SystemProgram): void {15  counter.bump = counter.create(authority, ["counter", authority.key]);16  counter.authority = authority.key;17  counter.count = 0n;18}19 20export function increment(authority: Signer, counter: Mut<Counter>, by: u64): void {21  require(counter.authority === authority.key, CounterError.Unauthorized);22  counter.count += by;23}24 25/** Read-only check that callers can simulate. */26export function assertAtLeast(counter: Account<Counter>, min: u64): void {27  require(counter.count >= min, "counter is below the expected minimum");28}29