eos_update_auth.js

const { Api, JsonRpc, RpcError } = require('eosjs');
const { JsSignatureProvider } = require('eosjs/dist/eosjs-jssig');
const fetch = require('node-fetch');
const { TextDecoder, TextEncoder } = require('text-encoding');

const signatureProvider = new JsSignatureProvider(["5JUVf4PgAppQciKbxngmmfWHsmaxGcfKu53X6zpKTK2zg25MsEn"]);
const rpc = new JsonRpc('http://node.dealin.io:1888', { fetch });
const api = new Api({
	rpc,
	signatureProvider,
	textDecoder: new TextDecoder(),
	textEncoder: new TextEncoder()
});

// creates a serialized EOS.IO transaction.
//
// this transaction can be then be signed separately and pushed
const createTransaction = async (account, name, actor, permission, data) => {

	try {
		return await api.transact({
			actions: [{
				account: account,
				name: name,
				authorization: [{
					actor: actor,
					permission: permission,
				}],
				data: data,
			}]
		}, {
				blocksBehind: 3,
				expireSeconds: 30,
				broadcast: false,
				sign: false
			});
	} catch (e) {
		if (e instanceof RpcError)
			console.log(JSON.stringify(e.json, null, 2));
	}
}

// Sign a serialized transaction, `unsigned`
//
// The value returned can be PUSHED to the HTTP  server 
const signTransaction = async (unsigned, provider) => {

	const keys = await provider.getAvailableKeys()
	unsigned.requiredKeys = keys
	// Dealin Node Chain ID -- can change.
	unsigned.chainId = "e70aaab8997e1dfce58fbfac80cbbb8fecec7b99cf982a9444273cbc64c41473"

	let sigs = unsigned.signatures || null
	const signed = await provider.sign(unsigned)

	if (sigs) {
		signed.signatures = signed.signatures.concat(sigs)
	}

	return signed
}

// configures EOS.IO account.
//
// adds the eosio.code pseudo-authority
const updateAuth = async (account, activePubKey, ownerPrivateKey) => {

	const txData = {
		// account to be configured
		account: account,
		auth: {
			accounts: [{
				permission: {
					// should always be the platform account
					actor: "dealination2",
					// the new pseudo-auth required for an account to use inline actions
					permission: "eosio.code"
				}, weight: 1
			}],
			keys: [
				{
					// active public key 
					key: activePubKey,
					weight: 1
				}
			],
			threshold: 1,
			waits: []
		},
		parent: "owner",
		permission: "active"
	}

	const serializedTx = await createTransaction(
		// platform account -- 'eosio' is the platform account for the eosio.system SC.
		"eosio",
		// action name
		"updateauth",
		// account signing this transaction
		account,
		// account permission
		"owner",
		// request body - action parameters
		txData
	);

	const signedTx = await signTransaction(
		serializedTx,
		// create a sig-provider with one private key
		new JsSignatureProvider([ownerPrivateKey]));

	const res = await rpc.push_transaction(signedTx);
	return res;
}

(async () => {

	const res = await updateAuth(
		// account to configure
		'ylervjtonchy',
		// active pub key
		'EOS7Vkw5ZKn2RkVyrz6jo1TEY2Afd4JotpsbmqTdeMkk4hMQFZLDm',
		// owner private key - updateauth transactions are signed using the owner private key
		'5KUXAxXYoKQrpwo4TsnMUn4vmG2zYrA9UwFxdAFF35TDABFypDc' 
	);

	console.log(res);
})();