Solana Kit

The @solana/accounts package provides types and helper methods for representing, fetching, and decoding Solana accounts. It offers a unified definition for accounts regardless of their retrieval method and supports both encoded (raw bytes) and decoded (structured data) representations.

Key features include:

• Unified account definitions.
• Support for MaybeAccount to handle accounts that may or may not exist on-chain.
• Helpers for fetching, parsing, and decoding accounts.
• Assertion utilities to verify account existence.

// Fetch.
const myAddress = address('1234..5678');
const myAccount = await fetchEncodedAccount(rpc, myAddress);
myAccount satisfies MaybeEncodedAccount<'1234..5678'>;

// Assert.
assertAccountExists(myAccount);
myAccount satisfies EncodedAccount<'1234..5678'>;

// Decode.
type MyAccountData = { name: string; age: number };
const myDecoder: Decoder<MyAccountData> = getStructDecoder([
    ['name', addDecoderSizePrefix(getUtf8Decoder(), getU32Decoder())],
    ['age', getU32Decoder()],
]);
const myDecodedAccount = decodeAccount(myAccount, myDecoder);
myDecodedAccount satisfies Account<MyAccountData, '1234..5678'>;

A Codec is an object that provides a bidirectional interface for transforming data between a structured type and a Uint8Array. It abstracts away the underlying serialization strategy and is highly composable, allowing you to build complex binary layouts from simple building blocks.

A Codec<From, To> has two primary methods:

• encode(value: From): Uint8Array
• decode(bytes: Uint8Array): To

Note that To can be a more specific type than From (e.g., encoding a number but decoding to a bigint).

import {
    Codec,
    addCodecSizePrefix,
    getUtf8Codec,
    getU32Codec,
    getStructCodec,
} from '@solana/kit';

type Person = { name: string; age: number };

const getPersonCodec = (): Codec<Person> =>
    getStructCodec([
        ['name', addCodecSizePrefix(getUtf8Codec(), getU32Codec())],
        ['age', getU32Codec()],
    ]);

const personCodec = getPersonCodec();
const encodedPerson = personCodec.encode({ name: 'John', age: 42 });
const decodedPerson = personCodec.decode(encodedPerson);