@polkadot-apps/tx

Transaction submission, lifecycle watching, and dev signers for Polkadot chains.

Install

pnpm add @polkadot-apps/tx

Peer dependency: polkadot-api must be installed in your project.

pnpm add polkadot-api

Quick start

import { submitAndWatch, createDevSigner } from "@polkadot-apps/tx";

const signer = createDevSigner("Alice");

const result = await submitAndWatch(tx, signer, {
  waitFor: "finalized",
  onStatus: (status) => console.log(status),
});

console.log(result.txHash, result.ok);

Batch transactions

Submit multiple transactions as a single atomic batch. Uses Substrate's Utility.batch_all by default (all-or-nothing).

import { batchSubmitAndWatch } from "@polkadot-apps/tx";

const tx1 = api.tx.Balances.transfer_keep_alive({ dest: addr1, value: 1_000n });
const tx2 = api.tx.Balances.transfer_keep_alive({ dest: addr2, value: 2_000n });
const tx3 = api.tx.System.remark({ remark: Binary.fromText("hello") });

const result = await batchSubmitAndWatch([tx1, tx2, tx3], api, signer, {
  onStatus: (status) => console.log(status),
});

Three batch modes are available:

| Mode | Behavior | |------|----------| | "batch_all" (default) | Atomic. Reverts all calls if any single call fails. | | "batch" | Best-effort. Stops at first failure but earlier successful calls are not reverted. | | "force_batch" | Like batch but continues after failures (never aborts early). |

// Non-atomic: some calls may fail while others succeed
const result = await batchSubmitAndWatch(calls, api, signer, { mode: "batch" });

WARNING: In "batch" and "force_batch" modes, result.ok is true even when individual calls fail. Inspect result.events for Utility.ItemFailed events to detect individual failures. Only "batch_all" guarantees that result.ok === false when any call fails.

Calls can be PAPI transactions (.decodedCall extracted automatically), Ink SDK AsyncTransaction wrappers (.waited resolved automatically), or raw decoded calls.

// Mix of raw decoded calls and transactions
const calls = [
  api.tx.Balances.transfer_keep_alive({ dest, value: 1_000n }),     // PAPI tx
  extractTransaction(await contract.query("mint", { origin, data })), // Ink SDK
  someDecodedCallObject,                                              // raw
];
const result = await batchSubmitAndWatch(calls, api, signer);

Transaction lifecycle

submitAndWatch drives a transaction through its full lifecycle: signing, broadcasting, block inclusion, and optional finalization. You choose when to resolve the returned promise with the waitFor option.

import { submitAndWatch } from "@polkadot-apps/tx";

const result = await submitAndWatch(tx, signer, {
  waitFor: "best-block",   // resolve at best-block inclusion (default)
  timeoutMs: 300_000,      // 5-minute timeout (default)
  mortalityPeriod: 256,    // ~43 minutes on Polkadot (default)
  onStatus: (status) => {
    // "signing" -> "broadcasting" -> "in-block" -> "finalized"
    updateUI(status);
  },
});

if (!result.ok) {
  console.error("Dispatch failed:", result.dispatchError);
}

The function accepts both raw PAPI transactions and Ink SDK AsyncTransaction wrappers. Ink SDK wrappers are resolved automatically via the .waited promise.

Dev signers

Create signers from the well-known Substrate dev mnemonic for local testing. All keys derive at //Name using sr25519.

import { createDevSigner, getDevPublicKey } from "@polkadot-apps/tx";

const alice = createDevSigner("Alice");
const bobPubKey = getDevPublicKey("Bob"); // Uint8Array (32 bytes)

Available names: "Alice", "Bob", "Charlie", "Dave", "Eve", "Ferdie".

Dry-run and weight buffers

Extract a submittable transaction from an Ink SDK dry-run result and apply a safety buffer to weight estimates before submission.

import { extractTransaction, applyWeightBuffer } from "@polkadot-apps/tx";

const dryRunResult = await contract.query.myMethod(args);
const tx = extractTransaction(dryRunResult);

const buffered = applyWeightBuffer(dryRunResult.weight_required, {
  percent: 25, // default: 25%
});

Account mapping

Map an SS58 address to an H160 address on Asset Hub. The operation is idempotent -- it returns null when the account is already mapped.

import { ensureAccountMapped, isAccountMapped } from "@polkadot-apps/tx";

const mapped = await isAccountMapped(address, checker);

if (!mapped) {
  const result = await ensureAccountMapped(address, signer, checker, api);
  // result is TxResult or null (if already mapped)
}

Retry logic

withRetry wraps any async function with exponential backoff and jitter. It does not retry TxDispatchError, TxBatchError, TxSigningRejectedError, or TxTimeoutError -- these represent terminal conditions that retrying cannot fix.

import { withRetry, calculateDelay } from "@polkadot-apps/tx";

const result = await withRetry(() => submitAndWatch(tx, signer), {
  maxAttempts: 3,     // total attempts including the first (default)
  baseDelayMs: 1_000, // initial backoff (default)
  maxDelayMs: 15_000, // backoff cap (default)
});

// Calculate delay directly for custom retry strategies
const delay = calculateDelay(2, 1_000, 15_000);

Error handling

All errors extend a common TxError base class. Use the specific error types and utility functions to handle failures precisely.

import {
  TxTimeoutError,
  TxDispatchError,
  TxSigningRejectedError,
  TxDryRunError,
  TxAccountMappingError,
  formatDispatchError,
  formatDryRunError,
  isSigningRejection,
} from "@polkadot-apps/tx";

try {
  await submitAndWatch(tx, signer);
} catch (error) {
  if (isSigningRejection(error)) {
    console.log("User cancelled signing");
  } else if (error instanceof TxDispatchError) {
    console.error(error.formatted, error.dispatchError);
  } else if (error instanceof TxTimeoutError) {
    console.error(`Timed out after ${error.timeoutMs}ms`);
  } else if (error instanceof TxDryRunError) {
    console.error(error.formatted, error.revertReason);
  }
}

API

submitAndWatch(tx, signer, options?): Promise<TxResult>

Submit a transaction and watch its lifecycle through to inclusion or finalization.

| Parameter | Type | Description | |-----------|------|-------------| | tx | SubmittableTransaction | Transaction with signSubmitAndWatch. Raw PAPI or Ink SDK. | | signer | PolkadotSigner | Signer from a wallet, Host API, or createDevSigner. | | options | SubmitOptions | Optional. See below. |

Throws: TxTimeoutError, TxDispatchError, TxSigningRejectedError.

batchSubmitAndWatch(calls, api, signer, options?): Promise<TxResult>

Batch multiple transactions into a single Substrate Utility batch and submit with lifecycle tracking.

| Parameter | Type | Description | |-----------|------|-------------| | calls | BatchableCall[] | Transactions, AsyncTransactions, or raw decoded calls. | | api | BatchApi | Typed API with tx.Utility.batch_all/batch/force_batch. | | signer | PolkadotSigner | Signer from a wallet, Host API, or createDevSigner. | | options | BatchSubmitOptions | Optional. Extends SubmitOptions with mode. |

Throws: TxBatchError (empty calls), TxTimeoutError, TxDispatchError, TxSigningRejectedError.

createDevSigner(name): PolkadotSigner

Create a signer from the well-known dev mnemonic at //Name (sr25519).

| Parameter | Type | Description | |-----------|------|-------------| | name | DevAccountName | One of "Alice", "Bob", "Charlie", "Dave", "Eve", "Ferdie". |

getDevPublicKey(name): Uint8Array

Return the 32-byte public key for a dev account.

withRetry<T>(fn, options?): Promise<T>

Retry an async function with exponential backoff and jitter. Does not retry TxBatchError, TxDispatchError, TxSigningRejectedError, or TxTimeoutError.

| Parameter | Type | Description | |-----------|------|-------------| | fn | () => Promise<T> | Async function to retry. | | options | RetryOptions | Optional retry configuration. |

calculateDelay(attempt, baseDelayMs, maxDelayMs): number

Compute the backoff delay for a given attempt number, with jitter.

extractTransaction(result): SubmittableTransaction

Extract a submittable transaction from an Ink SDK dry-run result.

applyWeightBuffer(weight, options?): Weight

Apply a percentage safety buffer to a weight estimate. Default buffer is 25%.

ensureAccountMapped(address, signer, checker, api, options?): Promise<TxResult | null>

Map an SS58 address to H160 on Asset Hub. Returns null if the account is already mapped.

isAccountMapped(address, checker): Promise<boolean>

Check whether an SS58 address is already mapped to an H160 address.

Error utilities

| Function | Signature | Description | |----------|-----------|-------------| | formatDispatchError | (result) => string | Format a dispatch error into a readable string. | | formatDryRunError | (result) => string | Format a dry-run error into a readable string. | | isSigningRejection | (error) => boolean | Check if an error is a signing rejection. |

Types

type TxStatus = "signing" | "broadcasting" | "in-block" | "finalized" | "error";

type WaitFor = "best-block" | "finalized";

interface TxResult {
  txHash: string;
  ok: boolean;
  block: { hash: string; number: number; index: number };
  events: unknown[];
  dispatchError?: unknown;
}

interface SubmitOptions {
  waitFor?: WaitFor;          // default: "best-block"
  timeoutMs?: number;         // default: 300_000
  mortalityPeriod?: number;   // default: 256
  onStatus?: (status: TxStatus) => void;
}

interface RetryOptions {
  maxAttempts?: number;   // default: 3
  baseDelayMs?: number;   // default: 1_000
  maxDelayMs?: number;    // default: 15_000
}

type DevAccountName = "Alice" | "Bob" | "Charlie" | "Dave" | "Eve" | "Ferdie";

interface Weight {
  ref_time: bigint;
  proof_size: bigint;
}

type BatchMode = "batch_all" | "batch" | "force_batch";

interface BatchSubmitOptions extends SubmitOptions {
  mode?: BatchMode;  // default: "batch_all"
}

interface BatchApi {
  tx: {
    Utility: {
      batch(args: { calls: unknown[] }): SubmittableTransaction;
      batch_all(args: { calls: unknown[] }): SubmittableTransaction;
      force_batch(args: { calls: unknown[] }): SubmittableTransaction;
    };
  };
}

Error classes

| Class | Extends | Key properties | |-------|---------|---------------| | TxError | Error | Base class for all tx errors. | | TxTimeoutError | TxError | timeoutMs: number | | TxDispatchError | TxError | dispatchError: unknown, formatted: string | | TxSigningRejectedError | TxError | User rejected signing. | | TxDryRunError | TxError | raw: unknown, formatted: string, revertReason?: string | | TxBatchError | TxError | Batch construction failed (e.g., empty calls). | | TxAccountMappingError | TxError | Account mapping failed. |

License

Apache-2.0