DelightfulDOT

A fast & lightweight JavaScript/TypeScript client for Polkadot & Substrate

Note: The project is still in active development phase, the information on this page might be outdated. Feel free to raise an issue if you run into any problems or want to share any ideas.

Have a quick taste

Try delightfuldot now on CodeSandbox Playground or follow the below steps to run it on your local environment.

• Install delightfuldot package

# via yarn
yarn add delightfuldot

# via npm
npm i delightfuldot

• Install @delightfuldot/chaintypes package for chain types & APIs suggestion. Skip this step if you don't use TypeScript.

# via yarn
yarn add -D @delightfuldot/chaintypes

# via npm
npm i -D @delightfuldot/chaintypes

• Initialize the API client and start interacting with Polkadot network

// main.ts
import { DelightfulApi } from 'delightfuldot';
import { PolkadotApi } from '@delightfuldot/chaintypes';

const run = async () => {
  const api = await DelightfulApi.new<PolkadotApi>('wss://rpc.polkadot.io');

  // Call rpc `state_getMetadata` to fetch raw scale-encoded metadata and decode it.
  const metadata = await api.rpc.state.getMetadata();
  console.log('Metadata:', metadata);

  // Query on-chain storage
  const address = '14...';
  const balance = await api.query.system.account(address);
  console.log('Balance:', balance);


  // Subscribe to on-chain storage changes
  const unsub = await api.query.system.number((blockNumber) => {
    console.log(`Current block number: ${blockNumber}`);
  });

  // Get pallet constants
  const ss58Prefix = api.consts.system.ss58Prefix;
  console.log('Polkadot ss58Prefix:', ss58Prefix)

  // await unsub();
  // await api.disconnect();
}

run().catch(console.error);

• You can also import delightfuldot using require.

// main.js
const { DelightfulApi } = require('delightfuldot');
// ...
const api = await DelightfulApi.new('wss://rpc.polkadot.io');

Table of contents

• Status
• Chain Types & APIs
• Execute RPC Methods
• Query On-chain Storage
• Constants
• Runtime APIs ⏳
• Submit Transactions ⏳
• Events
• Errors
• Credit

Status

| Feature | Status | | ----------- | ----------- | | Execute RPC (api.rpc) | ✅ | | Query on-chain storage (api.query) | ✅ | | Get runtime constants (api.consts) | ✅ | | Call runtime APIs (api.call) | ⏳ | | Transaction APIs (api.tx) | ⏳ | | Events (api.events) | ✅ | | Errors (api.errors) | ✅ | | Contract APIs | ⏳ | | Metadata v14 | ✅ | | Metadata v15 | ⏳ | | RPC v2 | ⏳ |

Chain Types & APIs

Each Substrate-based blockchain has their own set of data types & APIs to interact with, so being aware of those types & APIs when working with a blockchain will greatly improve the overall development experience. delightfuldot exposes TypeScript's types & APIs for each individual Substrate-based blockchain, we recommend using TypeScript for your project to have the best experience.

Types & APIs for each Substrate-based blockchains are defined in package @delightfuldot/chaintypes:

# via yarn
yarn add -D @delightfuldot/chaintypes

# via npm
npm i -D @delightfuldot/chaintypes

Initialize a DelighfulApi instance using the ChainApi interface for a target chain to enable types & APIs suggestion/autocompletion for that particular chain:

import { DelightfulApi } from 'delightfuldot';
import type { PolkadotApi, KusamaApi, MoonbeamApi, AstarApi } from '@delightfuldot/chaintypes';

// ...

const polkadotApi = await DelightfulApi.new<PolkadotApi>('wss://rpc.polkadot.io');
console.log(await polkadotApi.query.babe.authorities());

const kusamaApi = await DelightfulApi.new<KusamaApi>('wss://kusama-rpc.polkadot.io');
console.log(await kusamaApi.query.society.memberCount());

const moonbeamApi = await DelightfulApi.new<MoonbeamApi>('wss://wss.api.moonbeam.network');
console.log(await moonbeamApi.query.ethereumChainId.chainId());

const astarApi = await DelightfulApi.new<AstarApi>('wss://rpc.astar.network');
console.log(await astarApi.query.dappsStaking.blockRewardAccumulator());

const genericApi = await DelightfulApi.new('ws://localhost:9944');

// ...

In alpha test version, we only support ChainApi interfaces for 4 networks (Polkadot, Kusama, Moonbeam & Astar), we plan to expand this list to support more Substrate-based blockchains in the near future.

Execute RPC Methods

RPCs can be execute via api.rpc entry point. After creating a DelightfulApi instance with a ChainApi interface of the network you want to interact with, all RPC methods of the network will be exposed in the autocompletion/suggestion with format: api.rpc.<module>.<methodName>. E.g: you can find all supported RPC methods for Polkadot network here, similarly for other networks as well.

Examples:

// Call rpc: `state_getMetadata`
const metadata = await api.rpc.state.getMetadata(); 

// Call an arbitrary rpc: `module_rpc_name` with arguments ['param1', 'param2']
const result = await api.rpc.module.rpc_name('param1', 'param2');

Query On-chain Storage

On-chain storage can be query via api.query entry point. All the available storage entries for a chain are exposed in the ChainApi interface for that chain and can be execute with format: api.query.<pallet>.<storgeEntry>. E.g: You can find all the available storage queries of Polkadot network here, similarly for other networks as well.

Examples:

// Query account balance
const balance = await api.query.system.account(<address>);

// Get all events of current block
const events = await api.query.system.events();

Constants

Runtime constants (parameter types) are defined in metadata, and can be inspect via api.consts entry point with format: api.consts.<pallet>.<constantName>. All available constants are also exposed in the ChainApi interface. E.g: Available constants for Polkadot network is defined here, similarly for other networks.

Examples:

// Get runtime version
const runtimeVersion = api.consts.system.version;

// Get existential deposit in pallet balances
const existentialDeposit = api.consts.balances.existentialDeposit;

Runtime APIs

⏳ coming soon

Submit Transactions

⏳ coming soon

Events

Events for each pallet emit during runtime operations and are defined in the medata. Available events are also exposed in ChainApi interface so we can get information of an event through syntax api.events.<pallet>.<eventName>. E.g: Events for Polkadot network can be found here, similarly for other network as well.

This api.events is helpful when we want quickly check if an event matches with an event that we're expecting in a list of events, the API also comes with type narrowing for the matched event, so event name & related data of the event are fully typed.

Example to list new accounts created in each block:

// ...
const ss58Prefix = api.consts.system.ss58Prefix;
await api.query.system.events(async (eventRecords) => {
  const newAccountEvents = eventRecords
    .map(({ event }) => api.events.system.NewAccount.as(event))
    .filter((one) => one);

  console.log(newAccountEvents.length, 'account(s) was created in block', await api.query.system.number());

  newAccountEvents.forEach((event, index) => {
    console.log(`New Account ${index + 1}:`, event.palletEvent.data.account.address(ss58Prefix));
  });
});
// ...

Errors

Pallet errors are thrown out when things go wrong in the runtime, those are defined in the metadata. Available errors for each pallet are also exposed in ChainApi interface, so we can get information an error through this syntax: api.errors.<pallet>.<errorName>. E.g: Available errors for Polkadot network can be found here.

Similar to events API, this API is helpful when we want to check if an error maches with an error that we're expecting.

Example if an error is AlreadyExists from Assets pallet:

// ...
await api.query.system.events(async (eventRecords) => {
  for (const tx of eventRecords) {
    if (api.events.system.ExtrinsicFailed.is(tx.event)) {
      const { dispatchError } = tx.event.palletEvent.data;
      if (dispatchError.tag === 'Module' && api.errors.assets.AlreadyExists.is(dispatchError.value)) {
        console.log('Assets.AlreadyExists error occurred!');
      } else {
        console.log('Other error occurred', dispatchError);
      }
    }
  }
});
// ...

Credit

delightfuldot take a lot of inspirations from project @polkadot/api. A big thank to all the maintainers/contributors of this awesome library.

License

Apache-2.0