@dfinity/ledger-icp/README.md

A library for interfacing with the ICP ledger on the Internet Computer.

# ledger-icp-js

A library for interfacing with the [ICP ledger](https://internetcomputer.org/icp-tokens/) on the Internet Computer.

[![npm version](https://img.shields.io/npm/v/@dfinity/ledger-icp.svg?logo=npm)](https://www.npmjs.com/package/@dfinity/ledger-icp) [![GitHub license](https://img.shields.io/badge/license-Apache%202.0-blue.svg)](https://opensource.org/licenses/Apache-2.0)

> ℹ️ This library is meant to interface with the ICP ledger only. If you are looking to interact with Snses, ckBTC, or other ICRC tokens, use the [ledger-icrc-js](../ledger-icrc) library.

## Table of contents

- [Installation](#installation)
- [Usage](#usage)
- [Features](#features)
- [Resources](#resources)

## Installation

You can use `ledger-icp-js` by installing it in your project.

```bash
npm i @dfinity/ledger-icp
```

The bundle needs peer dependencies, be sure that following resources are available in your project as well.

```bash
npm i @dfinity/agent @dfinity/candid @dfinity/principal @dfinity/utils
```

## Usage

The features are available through the class `LedgerCanister`. It has to be instantiated with a canister ID.

e.g. fetching a token metadata.

```ts
import { createAgent } from "@dfinity/utils";
import { LedgerCanister } from "@dfinity/ledger-icp";

const agent = await createAgent({
  identity,
  host: HOST,
});

const { metadata } = LedgerCanister.create({
  agent,
  canisterId: MY_LEDGER_CANISTER_ID,
});

const data = await metadata();
```

## Features

`ledger-icp-js` implements following features:

<!-- TSDOC_START -->

### :factory: AccountIdentifier

A 32-byte account identifier used to send and receive ICP tokens.

The ICP Ledger uses the concept of an `AccountIdentifier` to represent accounts.
It’s a unique value derived from a principal (the identity controlling the account)
and a subaccount. This design allows a single principal to control multiple accounts
by using different subaccounts.

References:

- [https://internetcomputer.org/docs/references/ledger#\_accounts](https://internetcomputer.org/docs/references/ledger#_accounts)
- [https://internetcomputer.org/docs/defi/token-ledgers/setup/icp_ledger_setup](https://internetcomputer.org/docs/defi/token-ledgers/setup/icp_ledger_setup)
- [https://internetcomputer.org/docs/references/ledger#\_operations_transactions_blocks_transaction_ledger](https://internetcomputer.org/docs/references/ledger#_operations_transactions_blocks_transaction_ledger)

[:link: Source](https://github.com/dfinity/ic-js/tree/main/packages/ledger-icp/src/account_identifier.ts#L22)

#### Static Methods

- [fromHex](#gear-fromhex)
- [fromPrincipal](#gear-fromprincipal)

##### :gear: fromHex

Creates an `AccountIdentifier` object from a hexadecimal string (e.g. d3e13d4777e22367532053190b6c6ccf57444a61337e996242b1abfb52cf92c8).
Validates the checksum in the process.

| Method    | Type                                 |
| --------- | ------------------------------------ |
| `fromHex` | `(hex: string) => AccountIdentifier` |

Parameters:

- `hex`: - The 64-character hexadecimal representation of the account identifier.

Returns:

An instance of `AccountIdentifier`.

[:link: Source](https://github.com/dfinity/ic-js/tree/main/packages/ledger-icp/src/account_identifier.ts#L33)

##### :gear: fromPrincipal

Creates an `AccountIdentifier` object from a principal and optional subaccount.

When no subaccount is provided, a 32-byte array of zeros is used by default.
You can use any arbitrary 32 bytes as a subaccount identifier to derive a distinct account identifier
for the same principal.

| Method          | Type                                                                                                                 |
| --------------- | -------------------------------------------------------------------------------------------------------------------- |
| `fromPrincipal` | `({ principal, subAccount, }: { principal: Principal; subAccount?: SubAccount or undefined; }) => AccountIdentifier` |

Parameters:

- `options.principal`: - The principal to derive the account from.
- `options.subAccount`: - The optional subaccount (defaults to 0).

Returns:

An instance of `AccountIdentifier`.

[:link: Source](https://github.com/dfinity/ic-js/tree/main/packages/ledger-icp/src/account_identifier.ts#L67)

#### Methods

- [toHex](#gear-tohex)
- [toUint8Array](#gear-touint8array)
- [toNumbers](#gear-tonumbers)
- [toAccountIdentifierHash](#gear-toaccountidentifierhash)

##### :gear: toHex

Returns the ICP Ledger Account Identifier as a 64-character hexadecimal string.
This is the format typically used to display the account identifier in a human-readable way.

| Method  | Type           |
| ------- | -------------- |
| `toHex` | `() => string` |

Returns:

Hex representation (64-character string).

[:link: Source](https://github.com/dfinity/ic-js/tree/main/packages/ledger-icp/src/account_identifier.ts#L99)

##### :gear: toUint8Array

Returns the raw 32-byte `Uint8Array` of the account identifier.

| Method         | Type                                |
| -------------- | ----------------------------------- |
| `toUint8Array` | `() => Uint8Array<ArrayBufferLike>` |

Returns:

The raw bytes of the account identifier.

[:link: Source](https://github.com/dfinity/ic-js/tree/main/packages/ledger-icp/src/account_identifier.ts#L108)

##### :gear: toNumbers

Returns the account identifier as an array of numbers.

| Method      | Type             |
| ----------- | ---------------- |
| `toNumbers` | `() => number[]` |

Returns:

An array of byte values.

[:link: Source](https://github.com/dfinity/ic-js/tree/main/packages/ledger-icp/src/account_identifier.ts#L117)

##### :gear: toAccountIdentifierHash

Returns the raw bytes wrapped in an object under the `hash` key.

| Method                    | Type                                           |
| ------------------------- | ---------------------------------------------- |
| `toAccountIdentifierHash` | `() => { hash: Uint8Array<ArrayBufferLike>; }` |

Returns:

`{ hash: Uint8Array }` where `hash` is the raw 32-byte `Uint8Array`.

[:link: Source](https://github.com/dfinity/ic-js/tree/main/packages/ledger-icp/src/account_identifier.ts#L126)

### :factory: SubAccount

A subaccount in the ICP ledger is a 32-byte identifier that allows a principal (user or canister)
to control multiple independent accounts under the same principal.

References:

- [https://internetcomputer.org/docs/references/ledger#\_accounts](https://internetcomputer.org/docs/references/ledger#_accounts)

[:link: Source](https://github.com/dfinity/ic-js/tree/main/packages/ledger-icp/src/account_identifier.ts#L139)

#### Static Methods

- [fromBytes](#gear-frombytes)
- [fromPrincipal](#gear-fromprincipal)
- [fromID](#gear-fromid)

##### :gear: fromBytes

Creates a `SubAccount` from a 32‑byte array.

| Method      | Type                                                 |
| ----------- | ---------------------------------------------------- |
| `fromBytes` | `(bytes: Uint8Array<ArrayBufferLike>) => SubAccount` |

Parameters:

- `bytes`: - A `Uint8Array` of exactly 32 bytes.

Returns:

A `SubAccount` instance.

[:link: Source](https://github.com/dfinity/ic-js/tree/main/packages/ledger-icp/src/account_identifier.ts#L149)

##### :gear: fromPrincipal

Generates a `SubAccount` from a principal.

The principal is embedded into the beginning of a 32‑byte array.

| Method          | Type                                   |
| --------------- | -------------------------------------- |
| `fromPrincipal` | `(principal: Principal) => SubAccount` |

Parameters:

- `principal`: - A principal to encode into the subaccount.

Returns:

A `SubAccount` instance.

[:link: Source](https://github.com/dfinity/ic-js/tree/main/packages/ledger-icp/src/account_identifier.ts#L165)

##### :gear: fromID

Generates a `SubAccount` from a non‑negative number.

The number is encoded into the last 8 bytes of the 32‑byte array.
This is a common pattern when using numbered subaccounts like 0, 1, 2...

| Method   | Type                         |
| -------- | ---------------------------- |
| `fromID` | `(id: number) => SubAccount` |

Parameters:

- `id`: - A non-negative integer.

Returns:

A `SubAccount` instance.

[:link: Source](https://github.com/dfinity/ic-js/tree/main/packages/ledger-icp/src/account_identifier.ts#L188)

#### Methods

- [toUint8Array](#gear-touint8array)

##### :gear: toUint8Array

Returns the raw 32-byte `Uint8Array` representing this subaccount.

| Method         | Type                                |
| -------------- | ----------------------------------- |
| `toUint8Array` | `() => Uint8Array<ArrayBufferLike>` |

Returns:

A 32-byte array.

[:link: Source](https://github.com/dfinity/ic-js/tree/main/packages/ledger-icp/src/account_identifier.ts#L217)

### :factory: LedgerCanister

[:link: Source](https://github.com/dfinity/ic-js/tree/main/packages/ledger-icp/src/ledger.canister.ts#L35)

#### Static Methods

- [create](#gear-create)

##### :gear: create

| Method   | Type                                                  |
| -------- | ----------------------------------------------------- |
| `create` | `(options?: LedgerCanisterOptions) => LedgerCanister` |

[:link: Source](https://github.com/dfinity/ic-js/tree/main/packages/ledger-icp/src/ledger.canister.ts#L36)

#### Methods

- [accountBalance](#gear-accountbalance)
- [metadata](#gear-metadata)
- [transactionFee](#gear-transactionfee)
- [transfer](#gear-transfer)
- [icrc1Transfer](#gear-icrc1transfer)
- [icrc2Approve](#gear-icrc2approve)
- [icrc21ConsentMessage](#gear-icrc21consentmessage)

##### :gear: accountBalance

Returns the balance of the specified account identifier.

If `certified` is true, the request is fetched as an update call, otherwise
it is fetched using a query call.

| Method           | Type                                                                                                   |
| ---------------- | ------------------------------------------------------------------------------------------------------ |
| `accountBalance` | `({ accountIdentifier: accountIdentifierParam, certified, }: AccountBalanceParams) => Promise<bigint>` |

Parameters:

- `params`: The parameters to get the balance of an account.
- `params.accountIdentifier`: The account identifier provided either as hex string or as an AccountIdentifier.
- `params.certified`: query or update call.

Returns:

The balance of the given account.

[:link: Source](https://github.com/dfinity/ic-js/tree/main/packages/ledger-icp/src/ledger.canister.ts#L64)

##### :gear: metadata

Fetches the ledger metadata.

| Method     | Type                                                  |
| ---------- | ----------------------------------------------------- |
| `metadata` | `(params: QueryParams) => Promise<[string, Value][]>` |

Parameters:

- `params`: - The parameters used to fetch the metadata, notably query or certified call.

Returns:

The metadata of the ICP ledger. A promise that resolves to an array of metadata entries, where each entry is a tuple consisting of a string and a value.

[:link: Source](https://github.com/dfinity/ic-js/tree/main/packages/ledger-icp/src/ledger.canister.ts#L83)

##### :gear: transactionFee

Returns the transaction fee of the ICP ledger canister.

| Method           | Type                                        |
| ---------------- | ------------------------------------------- |
| `transactionFee` | `(params?: QueryParams) => Promise<bigint>` |

Parameters:

- `params`: - Optional query parameters for the request, defaulting to `{ certified: false }` for backwards compatibility reason.

Returns:

A promise that resolves to the transaction fee as a bigint.

[:link: Source](https://github.com/dfinity/ic-js/tree/main/packages/ledger-icp/src/ledger.canister.ts#L94)

##### :gear: transfer

Transfer ICP from the caller to the destination `accountIdentifier`.
Returns the index of the block containing the tx if it was successful.

| Method     | Type                                            |
| ---------- | ----------------------------------------------- |
| `transfer` | `(request: TransferRequest) => Promise<bigint>` |

[:link: Source](https://github.com/dfinity/ic-js/tree/main/packages/ledger-icp/src/ledger.canister.ts#L112)

##### :gear: icrc1Transfer

Transfer ICP from the caller to the destination `Account`.
Returns the index of the block containing the tx if it was successful.

| Method          | Type                                                 |
| --------------- | ---------------------------------------------------- |
| `icrc1Transfer` | `(request: Icrc1TransferRequest) => Promise<bigint>` |

[:link: Source](https://github.com/dfinity/ic-js/tree/main/packages/ledger-icp/src/ledger.canister.ts#L132)

##### :gear: icrc2Approve

This method entitles the `spender` to transfer token `amount` on behalf of the caller from account `{ owner = caller; subaccount = from_subaccount }`.

Reference: https://github.com/dfinity/ICRC-1/blob/main/standards/ICRC-2/README.md#icrc2_approve

| Method         | Type                                               |
| -------------- | -------------------------------------------------- |
| `icrc2Approve` | `(params: Icrc2ApproveRequest) => Promise<bigint>` |

Parameters:

- `params`: - The parameters to approve.

Returns:

The block index of the approved transaction.

[:link: Source](https://github.com/dfinity/ic-js/tree/main/packages/ledger-icp/src/ledger.canister.ts#L152)

##### :gear: icrc21ConsentMessage

Fetches the consent message for a specified canister call, intended to provide a human-readable message that helps users make informed decisions.

| Method                 | Type                                                                    |
| ---------------------- | ----------------------------------------------------------------------- |
| `icrc21ConsentMessage` | `(params: Icrc21ConsentMessageRequest) => Promise<icrc21_consent_info>` |

Parameters:

- `params`: - The request parameters containing the method name, arguments, and consent preferences (e.g., language).

Returns:

- A promise that resolves to the consent message response, which includes the consent message in the specified language and other related information.

[:link: Source](https://github.com/dfinity/ic-js/tree/main/packages/ledger-icp/src/ledger.canister.ts#L179)

### :factory: IndexCanister

[:link: Source](https://github.com/dfinity/ic-js/tree/main/packages/ledger-icp/src/index.canister.ts#L19)

#### Static Methods

- [create](#gear-create)

##### :gear: create

| Method   | Type                                                                                          |
| -------- | --------------------------------------------------------------------------------------------- |
| `create` | `({ canisterId: optionsCanisterId, ...options }: CanisterOptions<_SERVICE>) => IndexCanister` |

[:link: Source](https://github.com/dfinity/ic-js/tree/main/packages/ledger-icp/src/index.canister.ts#L20)

#### Methods

- [accountBalance](#gear-accountbalance)
- [getTransactions](#gear-gettransactions)

##### :gear: accountBalance

Returns the balance of the specified account identifier.

| Method           | Type                                                                           |
| ---------------- | ------------------------------------------------------------------------------ |
| `accountBalance` | `({ certified, accountIdentifier, }: AccountBalanceParams) => Promise<bigint>` |

Parameters:

- `params`: The parameters to get the balance of an account.
- `params.accountIdentifier`: The account identifier provided either as hex string or as an AccountIdentifier.
- `params.certified`: query or update call.

Returns:

The balance of the given account.

[:link: Source](https://github.com/dfinity/ic-js/tree/main/packages/ledger-icp/src/index.canister.ts#L45)

##### :gear: getTransactions

Returns the transactions and balance of an ICP account.

| Method            | Type                                                                                                                                              |
| ----------------- | ------------------------------------------------------------------------------------------------------------------------------------------------- |
| `getTransactions` | `({ certified, accountIdentifier, start, maxResults: max_results, }: GetTransactionsParams) => Promise<GetAccountIdentifierTransactionsResponse>` |

Parameters:

- `params`: The parameters to get the transactions.
- `params.certified`: query or update call.
- `params.accountIdentifier`: The account identifier provided either as hex string or as an AccountIdentifier.
- `params.start`: If set then the results will start from the next most recent transaction id after start (start won't be included). If not provided, then the results will start from the most recent transaction id.
- `params.maxResults`: Maximum number of transactions to fetch.

Returns:

The transactions, balance and the transaction id of the oldest transaction the account has.

[:link: Source](https://github.com/dfinity/ic-js/tree/main/packages/ledger-icp/src/index.canister.ts#L64)

<!-- TSDOC_END -->

## Resources

- [Ledger & Tokenization Working Group Standards](https://github.com/dfinity/ICRC-1/)
- [ICP ledger](https://github.com/dfinity/ic/tree/master/rs/rosetta-api/icp_ledger)