@ashkuc/xcm-estimate

xcm-estimate

xcm-estimate is a package designed to provide tools for estimating the XCM properties of a chain and the effects of XCM program execution.

Installation

Before installing xcm-estimate package to your project, you need to setup Yarn 2, due to requirements of the open-xcm-tools packages.

Yarn 2 (Berry) installation

First, set up a global Yarn, which will be used to create local instances:

npm install -g yarn

Then you need to locally change Yarn version for your project. In project folder:

yarn set version berry

After this actions you can use Yarn as usually (init project, add dependencies, etc.)

xcm-estimate installation

yarn add @ashkuc/xcm-estimate

Usage

The Estimator class provides a comprehensive framework for estimating fees and execution effects of cross-chain message (XCM) programs using Runtime API. It enables seamless interactions and efficient resource management by leveraging dry-run simulations and dynamic fee calculations based on the connected chain's XCM Runtime API reports.

Estimator creation

Define the chain identity:

const chainIdentity: ChainIdentity = {
  name: 'AssetHub',
  universalLocation: parachainUniversalLocation('polkadot', 1000n),
};

Use the constructor of Estimator to create an instance of this class:

const api = /* an instance of the `ApiPromise` */;
const xcmVersion = /* xcm version to use to communicate with the chain */
const estimator = new Estimator(api, chainIdentity, xcmVersion);

The Estimator can estimate the XCM version by itself (see estimateMaxXcmVersion) and it also can create the ApiPromise instance internally. If you want to pass the ChainInfo (which is the chain identity + list of endpoints) and make the Estimator to "just connect", you can use the connect method.

Estimator.connect(<ChainInfo>{
  identity: {
    name: 'AssetHub',
    universalLocation: parachainUniversalLocation('polkadot', 1000n),
  },
  endpoints: [
    'wss://asset-hub-polkadot-rpc.dwellir.com',
    'wss://sys.ibp.network/asset-hub-polkadot',
    // Add more endpoints as needed
  ],
}),

Estimate extrinsic fees

Call the tryEstimateExtrinsicFees method to get the estimated fees for the specified extrinsic. Pass parameters for extrinsic estimation like Origin (from @ashkuc/xcm-types), feeAssetId and a constructed extrinsic.

const estimatedFees = await this.estimator.tryEstimateExtrinsicFees(
  {System: {Signed: '5GrwvaEF5zXb26Fz9rcQpDWS57CtERHpNehXCPcNoHGKutQY'}},
  api.tx.palletXcm.transferAssets(/* parameters */),
  <AssetId>{
    parents: 1n,
    interior: {
      x3: [{parachain: 1000n}, {palletInstance: 50n}, {generalIndex: 1984n}],
    },
  },
  {
    estimatorResolver: (universalLocation: InteriorLocation) =>
      Estimator.connect(
        this.registry.chainInfoByUniversalLocation(universalLocation),
      ),
  },
);

Dependencies

• @ashkuc/xcm-types
• @ashkuc/xcm-util