Added flow sample

.babelrc

@@ -1,5 +1,5 @@
 {
-	"presets": ["env"],
+	"presets": ["env", "flow"],
 	"plugins": ["transform-runtime"],
 	"env": {
 		"test": {

.eslintrc.json

@@ -3,11 +3,16 @@
 	"globals": {
 		"naclInstance": true
 	},
+	"parser": "babel-eslint",
+	"plugins": [
+		"flowtype"
+	],
 	"rules": {
 		"arrow-parens": ["error", "as-needed"],
 		"curly": "off",
 		"indent": "off",
 		"no-confusing-arrow": "off",
-		"no-mixed-operators": "off"
+		"no-mixed-operators": "off",
+		"flowtype/define-flow-type": 2
 	}
 }

.flowconfig

@@ -0,0 +1,10 @@
+[include]
+
+[ignore]
+.*/node_modules/cypress/dist/*
+
+[libs]
+flow/
+
+[version]
+^0.65.0

flow/types.js

@@ -0,0 +1,41 @@
+/*
+ * Copyright © 2017 Lisk Foundation
+ *
+ * See the LICENSE file at the top-level directory of this distribution
+ * for licensing information.
+ *
+ * Unless otherwise agreed in a custom licensing agreement with the Lisk Foundation,
+ * no part of this software, including this file, may be copied, modified,
+ * propagated, or distributed except according to the terms contained in the
+ * LICENSE file.
+ *
+ * Removal or modification of this copyright notice is prohibited.
+ *
+ * @flow
+ */
+
+declare type Options = {
+	ssl: boolean,
+	node: string,
+	randomPeer: boolean,
+	testnet: boolean,
+	port: string,
+	bannedPeers: Array<string>,
+	nethash: NethashOption,
+};
+
+declare type NethashOption = {
+	'Content-Type': string,
+	nethash: string,
+	broadhash: string,
+	os: string,
+	version: string,
+	minVersion: string,
+	port: string,
+	Accept: string,
+};
+
+declare type NethashOptions = {
+	mainnet: NethashOption,
+	testnet: NethashOption,
+};

package.json

@@ -14,6 +14,7 @@
 		"prettier": "prettier --write \"browsertest/{setup,runTests}.js\" \"{cypress/integration,src,test}/**/*.js\"",
 		"serve:browsertest": "http-server browsertest",
 		"jenkins": "grunt jenkins --verbose",
+		"flow": "flow",
 		"build": "grunt build",
 		"build:check": "node -e \"require('./dist-node')\"",
 		"build:browsertest": "grunt build-browsertest",
@@ -40,16 +41,20 @@
 	},
 	"devDependencies": {
 		"babel-cli": "=6.24.1",
+		"babel-eslint": "=8.2.1",
 		"babel-plugin-istanbul": "=4.1.4",
 		"babel-plugin-rewire": "=1.1.0",
 		"babel-plugin-transform-runtime": "=6.23.0",
 		"babel-preset-env": "=1.6.0",
+		"babel-preset-flow": "=6.23.0",
 		"chokidar-cli": "=1.2.0",
 		"coveralls": "=2.13.1",
 		"cypress": "=0.20.3",
 		"eslint-config-airbnb-base": "=11.3.1",
 		"eslint-config-lisk-base": "=0.1.0",
+		"eslint-plugin-flowtype": "=2.42.0",
 		"eslint-plugin-import": "=2.7.0",
+		"flow-bin": "=0.65.0",
 		"grunt": "=1.0.1",
 		"grunt-browserify": "=5.0.0",
 		"grunt-contrib-uglify": "=3.0.1",

src/api/liskApi.js

@@ -11,14 +11,16 @@
  *
  * Removal or modification of this copyright notice is prohibited.
  *
+ * @flow
+ *
  */
 import config from '../../config.json';
 import { LIVE_PORT, TEST_PORT, GET, POST } from '../constants';
 import * as privateApi from './privateApi';
 import * as utils from './utils';
 
 export default class LiskAPI {
-	constructor(providedOptions) {
+	constructor(providedOptions: Options) {
 		const options = Object.assign({}, config.options, providedOptions);
 
 		this.defaultNodes = options.nodes || config.nodes.mainnet;
@@ -40,7 +42,35 @@ export default class LiskAPI {
 		this.nethash = this.getNethash(options.nethash);
 	}
 
-	getNethash(providedNethash) {
+	defaultNodes: Array<string>;
+	defaultSSLNodes: Array<string>;
+	defaultTestnetNodes: Array<string>;
+	options: Options;
+	ssl: boolean;
+	randomNode: boolean;
+	testnet: boolean;
+	bannedNodes: Array<string>;
+	node: string;
+	port: string;
+	nethash: NethashOption;
+
+	getAccount: Function;
+	getActiveDelegates: Function;
+	getStandbyDelegates: Function;
+	searchDelegatesByUsername: Function;
+	getBlocks: Function;
+	getForgedBlocks: Function;
+	getBlock: Function;
+	getTransactions: Function;
+	getTransaction: Function;
+	getVotes: Function;
+	getVoters: Function;
+	getUnsignedMultisignatureTransactions: Function;
+	getDapp: Function;
+	getDapps: Function;
+	getDappsByCategory: Function;
+
+	getNethash(providedNethash: string): NethashOption {
 		const { port } = this;
 		const NetHash = this.testnet
 			? utils.netHashOptions({ port }).testnet
@@ -65,12 +95,12 @@ export default class LiskAPI {
 		};
 	}
 
-	setNode(node) {
+	setNode(node: string) {
 		this.node = node || privateApi.selectNewNode.call(this);
 		return this.node;
 	}
 
-	setTestnet(testnet) {
+	setTestnet(testnet: boolean) {
 		if (this.testnet !== testnet) {
 			this.bannedNodes = [];
 		}
@@ -80,31 +110,35 @@ export default class LiskAPI {
 		privateApi.selectNewNode.call(this);
 	}
 
-	setSSL(ssl) {
+	setSSL(ssl: boolean) {
 		if (this.ssl !== ssl) {
 			this.ssl = ssl;
 			this.bannedNodes = [];
 			privateApi.selectNewNode.call(this);
 		}
 	}
 
-	broadcastTransactions(transactions) {
+	broadcastTransactions(transactions: Array<Object>) {
 		return privateApi.sendRequestPromise
 			.call(this, POST, 'transactions', transactions)
 			.then(result => result.body);
 	}
 
-	broadcastTransaction(transaction) {
+	broadcastTransaction(transaction: Object) {
 		return this.broadcastTransactions([transaction]);
 	}
 
-	broadcastSignatures(signatures) {
+	broadcastSignatures(signatures: Object) {
 		return privateApi.sendRequestPromise
 			.call(this, POST, 'signatures', { signatures })
 			.then(result => result.body);
 	}
 
-	sendRequest(requestMethod, requestType, options) {
+	sendRequest(
+		requestMethod: string,
+		requestType: string,
+		options: Object | Array<Object>,
+	) {
 		const checkedOptions = utils.checkOptions(options);
 
 		return privateApi.sendRequestPromise
@@ -128,7 +162,12 @@ export default class LiskAPI {
 			);
 	}
 
-	transferLSK(recipientId, amount, passphrase, secondPassphrase) {
+	transferLSK(
+		recipientId: string,
+		amount: number,
+		passphrase: string,
+		secondPassphrase: string,
+	) {
 		return this.sendRequest(POST, 'transactions', {
 			recipientId,
 			amount,

src/api/privateApi.js

@@ -11,22 +11,24 @@
  *
  * Removal or modification of this copyright notice is prohibited.
  *
+ * @flow
+ *
  */
 import * as popsicle from 'popsicle';
 import { GET } from '../constants';
 import * as utils from './utils';
 
-export function getNodes() {
+export function getNodes(): Array<string> {
 	if (this.testnet) return this.defaultTestnetNodes;
 	if (this.ssl) return this.defaultSSLNodes;
 	return this.defaultNodes;
 }
 
-export function isBanned(node) {
+export function isBanned(node: string): boolean {
 	return this.bannedNodes.includes(node);
 }
 
-export function getRandomNode() {
+export function getRandomNode(): string {
 	const nodes = getNodes.call(this).filter(node => !isBanned.call(this, node));
 
 	if (!nodes.length) {
@@ -39,7 +41,7 @@ export function getRandomNode() {
 	return nodes[randomIndex];
 }
 
-export function selectNewNode() {
+export function selectNewNode(): string {
 	const providedNode = this.options.node;
 
 	if (this.randomNode) {
@@ -58,23 +60,27 @@ export function selectNewNode() {
 	);
 }
 
-export function banActiveNode() {
+export function banActiveNode(): boolean {
 	if (!isBanned.call(this, this.node)) {
 		this.bannedNodes.push(this.node);
 		return true;
 	}
 	return false;
 }
 
-export function hasAvailableNodes() {
+export function hasAvailableNodes(): boolean {
 	const nodes = getNodes.call(this);
 
 	return this.randomNode
 		? nodes.some(node => !isBanned.call(this, node))
 		: false;
 }
 
-export function createRequestObject(method, requestType, providedOptions) {
+export function createRequestObject(
+	method: string,
+	requestType: string,
+	providedOptions: Object | Array<Object>,
+) {
 	const options = providedOptions || {};
 	const baseURL = utils.getFullURL(this);
 	const url =
@@ -90,7 +96,11 @@ export function createRequestObject(method, requestType, providedOptions) {
 	};
 }
 
-export function sendRequestPromise(requestMethod, requestType, options) {
+export function sendRequestPromise(
+	requestMethod: string,
+	requestType: string,
+	options: Object | Array<Object>,
+) {
 	const requestObject = createRequestObject.call(
 		this,
 		requestMethod,
@@ -104,11 +114,11 @@ export function sendRequestPromise(requestMethod, requestType, options) {
 }
 
 export function handleTimestampIsInFutureFailures(
-	requestMethod,
-	requestType,
-	options,
-	result,
-) {
+	requestMethod: string,
+	requestType: string,
+	options: any,
+	result: Object,
+): Promise<*> {
 	if (
 		!result.success &&
 		result.message &&
@@ -125,11 +135,11 @@ export function handleTimestampIsInFutureFailures(
 }
 
 export function handleSendRequestFailures(
-	requestMethod,
-	requestType,
-	options,
-	error,
-) {
+	requestMethod: string,
+	requestType: string,
+	options: Object | Array<Object>,
+	error: Error,
+): Promise<*> {
 	const that = this;
 	if (hasAvailableNodes.call(that)) {
 		return new Promise((resolve, reject) => {