This library provides additional typing information for user to access ChainX Network by using polkadot.js.
- Wallet: https://dapps.chainx.org
- explorer: https://scan.chainx.org
- polkadot docx： https://polkadot.js.org/docs/
- Install dependencies
yarn add @polkadot/api @chainx-v2/api- Create API instance
const { ApiPromise } = require('@polkadot/api');
const { WsProvider } = require('@polkadot/rpc-provider');
const { options } = require('@chainx-v2/api');
async function main() {
const wsProvider = new WsProvider('wss://mainnet.spiderx.pro/ws');
const api = await ApiPromise.create(options({ provider: wsProvider }));
await api.isReady;
// use api
const [chain, nodeName, nodeVersion] = await Promise.all([
api.rpc.system.chain(),
api.rpc.system.name(),
api.rpc.system.version()
]);
console.log(`You are connected to chain ${chain} using ${nodeName} v${nodeVersion}`);
}
main()- Listen to new blocks
This example shows how to subscribe to new blocks.
It displays the block number every time a new block is seen by the node you are connected to.
// Import the API
const { ApiPromise } = require('@polkadot/api');
const { WsProvider } = require('@polkadot/rpc-provider');
const { options } = require('@chainx-v2/api');
async function main () {
// the API has connected to the node and completed the initialisation process
const wsProvider = new WsProvider('wss://mainnet.chainx.org/ws');
const api = await ApiPromise.create(options({ provider: wsProvider }));
await api.isReady;
// We only display a couple, then unsubscribe
let count = 0;
// Subscribe to the new headers on-chain. The callback is fired when new headers
// are found, the call itself returns a promise with a subscription that can be
// used to unsubscribe from the newHead subscription
const unsubscribe = await api.rpc.chain.subscribeNewHeads((header) => {
console.log(`Chain is at block: #${header.number}`);
if (++count === 256) {
unsubscribe();
process.exit(0);
}
});
}
main().catch(console.error);- Listen to balance changes
This example shows how to instantiate a Polkadot and ChainX API object and use it to connect to a node and retrieve balance updates.
// Import the API
const { ApiPromise } = require('@polkadot/api');
const { WsProvider } = require('@polkadot/rpc-provider');
const { options } = require('@chainx-v2/api');
// Known account we want to use (available on dev chain, with funds)
const Alice = '5GrwvaEF5zXb26Fz9rcQpDWS57CtERHpNehXCPcNoHGKutQY';
async function main () {
// the API has connected to the node and completed the initialisation process
const wsProvider = new WsProvider('wss://mainnet.spiderx.pro/ws');
const api = await ApiPromise.create(options({ provider: wsProvider }));
await api.isReady;
// Retrieve the initial balance. Since the call has no callback, it is simply a promise
// that resolves to the current on-chain value
let { data: { free: previousFree }, nonce: previousNonce } = await api.query.system.account(Alice);
console.log(`${Alice} has a balance of ${previousFree}, nonce ${previousNonce}`);
console.log(`You may leave this example running and transfer any value to ${Alice}`);
// Here we subscribe to any balance changes and update the on-screen value
api.query.system.account(Alice, ({ data: { free: currentFree }, nonce: currentNonce }) => {
// Calculate the delta
const change = currentFree.sub(previousFree);
// Only display positive value changes (Since we are pulling `previous` above already,
// the initial balance change will also be zero)
if (!change.isZero()) {
console.log(`New balance change of ${change}, nonce ${currentNonce}`);
previousFree = currentFree;
previousNonce = currentNonce;
}
});
}
main().catch(console.error);- Listen to balance changes
This example shows how to instantiate a Polkadot API and ChainX API object and use it to connect to a node and retrieve balance updates.\
// Import the API
const { ApiPromise } = require('@polkadot/api');
const { WsProvider } = require('@polkadot/rpc-provider');
const { options } = require('@chainx-v2/api');
// Known account we want to use (available on dev chain, with funds)
const ALICE = '5GrwvaEF5zXb26Fz9rcQpDWS57CtERHpNehXCPcNoHGKutQY';
const BOB = '5FHneW46xGXgs5mUiveU4sbTyGBzmstUspZC92UhjJM694ty';
async function main () {
// the API has connected to the node and completed the initialisation process
const wsProvider = new WsProvider('wss://mainnet.spiderx.pro/ws');
const api = await ApiPromise.create(options({ provider: wsProvider }));
await api.isReady;
console.log('Tracking balances for:', [ALICE, BOB]);
// Subscribe and listen to several balance changes
api.query.system.account.multi([ALICE, BOB], (balances) => {
console.log('Change detected, new balances: ', balances.map(({ data: { free } }) => free));
});
}
main().catch(console.error);- Unsubscribe from listening to updates
This example shows how to subscribe to and later unsubscribe from listening to block updates.
In this example we're calling the built-in unsubscribe() function after a timeOut of 20s to cleanup and unsubscribe from listening to updates.
const { ApiPromise } = require('@polkadot/api');
const { WsProvider } = require('@polkadot/rpc-provider');
const { options } = require('@chainx-v2/api');
// Known account we want to use (available on dev chain, with funds)
const ALICE = '5GrwvaEF5zXb26Fz9rcQpDWS57CtERHpNehXCPcNoHGKutQY';
const BOB = '5FHneW46xGXgs5mUiveU4sbTyGBzmstUspZC92UhjJM694ty';
async function main () {
// the API has connected to the node and completed the initialisation process
const wsProvider = new WsProvider('wss://testnet-1.chainx.org/ws');
const api = await ApiPromise.create(options({ provider: wsProvider }));
await api.isReady;
// Subscribe to chain updates and log the current block number on update.
const unsubscribe = await api.rpc.chain.subscribeNewHeads((header) => {
console.log(`Chain is at block: #${header.number}`);
});
// In this example we're calling the unsubscribe() function that is being
// returned by the api call function after 20s.
setTimeout(() => {
unsubscribe();
console.log('Unsubscribed');
}, 20000);
}
main().catch(console.error);- Traverse events
Query the system events and extract information from them. This example runs until exited via Ctrl-C
// Import the API
const { ApiPromise } = require('@polkadot/api');
const { WsProvider } = require('@polkadot/rpc-provider');
const { options } = require('@chainx-v2/api');
async function main () {
// Create our API with a default connection to the local node
const wsProvider = new WsProvider('wss://mainnet.spiderx.pro/ws');
const api = await ApiPromise.create(options({ provider: wsProvider }));
await api.isReady;
// Subscribe to system events via storage
api.query.system.events((events) => {
console.log(`\nReceived ${events.length} events:`);
// Loop through the Vec<EventRecord>
events.forEach((record) => {
// Extract the phase, event and the event types
const { event, phase } = record;
const types = event.typeDef;
// Show what we are busy with
console.log(`\t${event.section}:${event.method}:: (phase=${phase.toString()})`);
console.log(`\t\t${event.meta.documentation.toString()}`);
// Loop through each of the parameters, displaying the type and data
event.data.forEach((data, index) => {
console.log(`\t\t\t${types[index].type}: ${data.toString()}`);
});
});
});
}
main().catch((error) => {
console.error(error);
process.exit(-1);
});- Use Api To Transfer Balance
const { ApiPromise, WsProvider } = require('@polkadot/api');
const { PAIRS } = require('@polkadot/keyring/testing');
const testKeyring = require('@polkadot/keyring/testing').default;
const { encodeAddress } = require('@polkadot/keyring');
const { options } =require('@chainx-v2/api');
const url = 'wss://testnet-1.chainx.org/ws';
const wsProvider = new WsProvider(url);
const keyring = testKeyring();
const alice = keyring.pairs[0];
// eslint-disable-next-line no-void
async function excuteTransfer () {
const api = await ApiPromise.create(options({ provider: wsProvider }));
const aliceAddr = encodeAddress(PAIRS[0].publicKey, 42);
const systemProperties = await api.rpc.system.properties();
console.log(aliceAddr);
const balance = await api.query.system.account(PAIRS[0].publicKey);
console.log('balance', balance.data.free.toString());
const toAddress = '5ChcBJcpSPojToxRCNSSYckpLkfPUg42o6wXv6Vo878Z54SR';
const transfer = api.tx.balances.transfer(toAddress, 1000000 * Math.pow(10, 8));
// Sign and send the transaction using our account
const hash = await transfer.signAndSend(alice);
console.log('Transfer sent with hash', hash.toHex());
process.exit();
}
async function main () {
await excuteTransfer();
}Polkadot/Substrate provides a utility.batch method that can be used to send a number of transactions at once. These are then executed from a single sender (single nonce specified) in sequence. This is very useful in a number of cases, for instance if you wish to create a payout for a validator for multiple eras, you can use this method. Likewise, you can send a number of transfers at once. Or even batch different types of transactions.
// Import the API
const { ApiPromise } = require('@polkadot/api');
const { WsProvider } = require('@polkadot/rpc-provider');
const { options } = require('@chainx-v2/api');
async function main () {
// Create our API with a default connection to the local node
const wsProvider = new WsProvider('wss://mainnet.chainx.org/ws');
const api = await ApiPromise.create(options({ provider: wsProvider }));
await api.isReady;
// Subscribe to system events via storage
// transfer with memo
const txs = [
api.tx.balances.transfer(addrBob, 12345),
api.tx.system.remark('test memo')
];
// construct the batch and send the transactions
api.tx.utility
.batch(txs)
.signAndSend(sender, ({ status }) => {
if (status.isInBlock) {
console.log(`included in ${status.asInBlock}`);
}
});
}
main().catch((error) => {
console.error(error);
process.exit(-1);
});
https://github.com/polkadot-js/tools/tree/master/packages/signer-cli
- api
- Contains necessary options to create a polkadot.js API instance