solana-program-examples/basics/close-account/native/ts/instructions/close.ts

import { Buffer } from 'node:buffer';
import { type PublicKey, SystemProgram, TransactionInstruction } from '@solana/web3.js';
import * as borsh from 'borsh';
import { MyInstruction } from '.';

export class Close {
  instruction: MyInstruction;

  constructor(props: {
    instruction: MyInstruction;
  }) {
    this.instruction = props.instruction;
  }

  toBuffer() {
    return Buffer.from(borsh.serialize(CloseSchema, this));
  }

  static fromBuffer(buffer: Buffer) {
    return borsh.deserialize(CloseSchema, Close, buffer);
  }
}

export const CloseSchema = new Map([
  [
    Close,
    {
      kind: 'struct',
      fields: [['instruction', 'u8']],
    },
  ],
]);

export function createCloseUserInstruction(target: PublicKey, payer: PublicKey, programId: PublicKey): TransactionInstruction {
  const instructionObject = new Close({
    instruction: MyInstruction.CloseUser,
  });

  const ix = new TransactionInstruction({
    keys: [
      { pubkey: target, isSigner: false, isWritable: true },
      { pubkey: payer, isSigner: true, isWritable: true },
      { pubkey: SystemProgram.programId, isSigner: false, isWritable: false },
    ],
    programId: programId,
    data: instructionObject.toBuffer(),
  });

  return ix;
}