Package Exports

@polkadot/api
@polkadot/api/index

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (@polkadot/api) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

@polkadot/api

This library provides a clean wrapper around all the methods exposed by a Polkadot network client.

Usage

Installation -

npm install --save @polkadot/api

Initialisation -

import Api from '@polkadot/api';
import WsProvider from '@polkadot/api-provider/ws';

const provider = new WsProvider('http://127.0.0.1:9944');
const api = new Api(provider);

Making calls -

api.chain
  .getHeader('0x1234567890')
  .then((header) => console.log(header))
  .catch((error) => console.error(error));

Retrieving the best block (once-off) -

api.chain
  .getHead()
  .then((headerHash) => {
    return api.chain.getHeader(headerHash);
  })
  .then((header) => {
    console.log(`best #${header.number.toString()}`);
  })
  .catch((error) => {
    console.error('error:', error);
  });

Retrieving best header via subscription -

api.chain
  .newHead((error, header) => {
    if (error) {
      console.error('error:', error);
    }

    console.log(`best #${header.number.toString()}`);
  })
  .then((subscriptionId) => {
    // id for the subscription, can unsubscribe via
    // api.chain.newHead.unsubscribe(subscriptionId)
  })
  .catch((error) => {
    console.error('error subscribing:', error);
  });