Assembly Script SDK

import { context, storage, logging } from "near-sdk-as";

// --- contract code goes below

// Under this key, we will store/retrieve the last sender account in the NEAR blockcahin.
const LAST_SENDER_KEY  = 'last_sender'

// This is our change method. It modifies the state of the contract by
// storing the account_id of the sender under the key "last_sender" on the blockchain
export function sayHi(param:string|null = null): string {
  // context.sender is the account_id of the user who sent this call to the contract
  // It's provided by the Blockchain runtime. For now we just store it in a local variable.
  const sender = context.sender;
  // `near` class contains some helper functions, e.g. logging.
  // Logs are not persistently stored on the blockchain, but produced by the blockchain runtime.
  // It's helpful to use logs for debugging your functions or when you need to get some info
  // from the change methods (since change methods don't return values to the front-end).
  logging.log(sender + ' says "Hi!"');

	if(param)
		logging.log('sayHi param: '+param);

  // storage is a helper class that allows contracts to modify the persistent state
  // and read from it. setString allows you to persistently store a string value for a given string key.
  // We'll store the last sender of this contract who called this method.
  storage.setString(LAST_SENDER_KEY, sender);
	return sender + ' said Hi!';
}

// This is our view method. It returns the last account_id of a sender who called `sayHi`.
// It reads value from the persistent store under the key "last_sender" and returns it.
export function whoSaidHi(param:string|null = null): string | null {
  // getString returns a string value for a given string key.
	logging.log('whoSaidHi "Hello World Log!"');

	if(param)
		logging.log('whoSaidHi param: '+param);

  return storage.getString(LAST_SENDER_KEY);
}