feat(options): Allow a custom options object as paramater

README.md

@@ -3,3 +3,64 @@
 [![Build passing](https://img.shields.io/travis/TheWorm/isomorphic-is-online.svg)](https://travis-ci.org/TheWorm/isomorphic-is-online)
 [![Code coverage](https://img.shields.io/codecov/c/github/theworm/isomorphic-is-online.svg)](https://codecov.io/github/theworm/isomorphic-is-online)
 [![Release version](https://img.shields.io/github/release/theworm/isomorphic-is-online.svg)](https://www.npmjs.com/package/isomorphic-is-online)
+
+A simple utility you can use to know if you are online or not.
+
+It relies on [cross-fetch](https://github.com/lquixada/cross-fetch), thus it aims to work on Node, React Native and Web (with browserify / webpack) environments.
+
+## Installation
+
+At the command-line terminal:
+
+```bash
+npm install --save isomorphic-is-online
+```
+
+Then in your code:
+
+```javascript
+// Using ES6 modules with Babel or TypeScript
+import isOnline from "isomorphic-is-online";
+
+// Using CommonJS modules
+const isOnline = require("isomorphic-is-online").default;
+```
+
+## Usage
+
+```javascript
+import isOnline from "isomorphic-is-online";
+
+console.log("Are you able to reach the internet?");
+isOnline().then(isOnline => {
+  console.log("Response:", isOnline);
+});
+```
+
+`isOnline` returns a promise which resolves to `true` if a connection can be established and resolves to `false` if it cannot or the network requests time out.
+
+| para
+
+## Default and custom options
+
+An optional object can be passed to `isOnline` to customize some options:
+
+| option  | type             | default       | description                                        |
+| ------- | ---------------- | ------------- | -------------------------------------------------- |
+| urls    | array of strings | ["//1.1.1.1"] | List of urls to request to check connection status |
+| timeout | number           | 3000          | Milliseconds to wait before timing out the request |
+
+```javascript
+const options = {
+  urls: ["https://apple.com", "//1.1.1.1"],
+  timeout: 5000
+};
+
+isOnline(options).then(isOnline => {
+  if (isOnline) {
+    hackTheInternet();
+  } else {
+    beQuiet();
+  }
+});
+```

src/index.js

@@ -4,10 +4,23 @@ import fetch from "cross-fetch";
 
 const isString = s => typeof s === "string" || s instanceof String;
 
-const isOnline = async (customUrls: Array<string>, timeout: number = 3000) => {
-  let urls = ["//1.1.1.1"];
-  if (Array.isArray(customUrls) && customUrls.every(isString)) {
-    urls = customUrls;
+type options = {
+  urls: Array<string>,
+  timeout: number
+};
+
+const defaultOptions: options = {
+  urls: ["//1.1.1.1"],
+  timeout: 3000
+};
+
+const isOnline = async (options: options) => {
+  let { urls, timeout } = options;
+  if (!Array.isArray(urls) || !urls.every(isString)) {
+    urls = defaultOptions.urls;
+  }
+  if (!timeout || typeof timeout !== "number") {
+    timeout = defaultOptions.timeout;
   }
   const onlinePromise = new Promise((resolve, reject) => {
     let failedUrls = 0;