Version: 21.01.2020

1) Initializing the Tracking

Focal.init(APP_ID, APP_TOKEN,READ_FUNC, WRITE_FUNC, FETCH_FUNC);

• Call this function before you use any other tracking method
• You find the APP_ID and the APP_TOKEN in the Focal login area -> Settings section
• For WRITE_FUNC and READ_FUNC, provide asynchronous functions to read and write any kind of persistent storage, e.g.
  • LocalStorage for a simple web application
  • AsyncStorage for React Native (https://docs.expo.io/versions/latest/sdk/async-storage/)
• Make sure that your READ_FUNC returns an empty object {} if the storage key does not yet exist (see example)
• For FETCH_FUNC, provide your usual fetch function. Note that for web applications, it might be necessary to provide window.fetch.bind(window) and for node-based applications, you have to use a library such as node-fetch

Example integration: React native application

import { AsyncStorage } from 'react-native';
const APP_ID=27;
const APP_TOKEN="TESTTOKEN";
const FocalWriteFunction = async (key, jsonObj) => {
  try {
    await AsyncStorage.setItem(
      key,
      JSON.stringify(jsonObj)
    );
  } catch (error) {
    // Handle errors for write function
  }
}
const FocalReadFunction = async (key) => {
  try {
    const value = await AsyncStorage.getItem(key);
    if (value !== null) {
      return JSON.parse(value);
    }
    return {}
  } catch (error) {
    // Handle errors for read function
  }
}
Focal.init (APP_ID,APP_TOKEN, FocalReadFunction, FocalWriteFunction, fetch)

2) Register a new user / device

• After initializing the Focal tracking using Focal.init, you need to register the new user or device
• You should run this whenever the app is started in case a user has cleared the persistent storage (e.g. local storage). It will not do anything if the device has already been registered.
• If you want, for any reason, to reset and register a device again, you have to call Focal.resetDevice() first, which will clean the configuration and event storage. If you only want to obtain a new Focal ID, you can also set the FORCE_NEW_FOCAL_ID flag (this is NOT the unique device id!).
• In order to register a device, you will need to have the following information:
  • Screen resolution of the device as integers
  • User-Agent
  • Optional: a UNIQUE_DEVICE_ID. If you set a unique device id, make sure that a custom variable with the label unique_device_id exists in the Focal login area under Settings.

Focal.registerDevice(RESOLUTION_X, RESOLUTION_Y, USER_AGENT, UNIQUE_DEVICE_ID, FORCE_NEW_FOCAL_ID)

• you can set FORCE_NEW_ID to true if you want to acquire a new Focal ID and/or disable the Focal device recognition (which uses the User-Agent string to recognize previously registered devices). Defaults to false.

Example integration: React native application

• For react native applications, we suggest to use the react-native-device-info package (https://www.npmjs.com/package/react-native-device-info) to get both a user agent string and a unique device id
• For expo, you can use Constants.getWebViewUserAgentAsync()(https://docs.expo.io/versions/latest/sdk/constants/) to get the user agent and Constants.deviceId to get a device id
• An example of the device registration can look likt this

import { Dimensions } from 'react-native';
import { getUniqueId, getUserAgent } from 'react-native-device-info';

// Call this function when your app starts, e.g. in your App() function
async function initFocal() {
  const {width, height} = Dimensions.get("window");
  await Focal.init(APP_ID,APP_TOKEN, TestReadFunction, TestWriteFunction, window.fetch.bind(window));
  const userAgent = await getUserAgent();
  const uniqueDeviceId = await getUniqueId();
  await Focal.registerDevice(width, height, userAgent, uniqueDeviceId);
  await Focal.trackView("Initial View Name");
}

3) Tracking views

• Views are different screens that your users open, such as a Home view or a Login view
• Whenever a user opens your app, you want to track the initial view and all changes, so make sure to implement the tracking of all view changes
• Note that before you can track any other event such as clicks or scrolls, you need to track a view. Doing so, our tracking knows where other events happen without proving the context to every event.

Focal.trackView(VIEW_NAME);

• a VIEW_NAME can be any string that describes the view such as "Home" or "Login". View names that include special chars or spaces will be transformed to friendly names, e.g. "Welcome Screen" will become "Welcome_Screen"

4) Update viewport dimensions

• Focal supports different dimension parameters that you can set using the setDimensionParameters method, e.g. the following call sets the screen width to 1024 (px)

Focal.setDimensionParameters( { 
   [DimensionParameters.SCREEN_WIDTH]: 1024
   });
Focal.trackDimensionUpdate();

• Note: SCREEN_WIDTH and SCREEN_HEIGHT default to the values you have set in the registerDevice() call
• Note that to actually track the changes, you need to additionally call Focal.trackDimensionUpdate() after setting a dimension parameter. Focal automatically tracks the dimensions you have set after every trackView() call
• The following different dimension parameters exist (defined in the DimensionParameters enum)

| ENUM | Description | JavaScript Reference | |------|-------------|----------------------| |DimensionParameters.SCREEN_WIDTH | Screen width (px)|screen.width| |DimensionParameters.SCREEN_HEIGHT | Screen height (px)|screen.height| |DimensionParameters.ORIENTATION_ANGLE | Orientation angle|screen.orientation.angle| |DimensionParameters.AVAILABLE_WIDTH | Screen available width (e.g. without bookmark panel, etc.)|screen.availWidth| |DimensionParameters.AVAILABLE_HEIGHT | Screen available height (e.g. without bookmark panel, etc.)|screen.availHeight| |DimensionParameters.SCROLL_WIDTH | Page wideness / scroll width (px)|document.documentElement.scrollHeight| |DimensionParameters.SCROLL_HEIGHT | Page length / scroll height (px)|document.documentElement.scrollHeight| |DimensionParameters.INNER_WIDTH | inner width: viewport including scrollbar|window.innerWidth| |DimensionParameters.INNER_HEIGHT | inner height: viewport including scrollbar|window.innerHeight| |DimensionParameters.CLIENT_WIDTH | client width: viewport without scrollbar|document.documentElement.clientWidth| |DimensionParameters.CLIENT_HEIGHT | client height: viewport without scrollbar|document.documentElement.clientHeight| |DimensionParameters.OUTER_WIDTH | outer width: window size (e.g. of the browser)|window.outerWidth| |DimensionParameters.OUTER_HEIGHT | outer height: window size (e.g. of the browser)|window.outerHeight| |DimensionParameters.SCREEN_X | Window position x |window.screenX| |DimensionParameters.SCREEN_Y | Window position y |window.screenY| |DimensionParameters.DEVICE_PIXEL_RATIO | The dpr parameter provides a means to multiply image dimensions in order to translate logical pixels (also 'CSS pixels') into physical pixels. The device pixel ratio is therefore the ratio between physical pixels and logical pixels. |window.devicePixelRatio|

5) Tracking orientation changes (usually necessary for mobile devices)

• Orientation change (e.g. from landscape to portrait) is a separate event that tracks the orientation angle. If you do not get angles/numbers from your function, use the values 0 for portrait and 90 for landscape.

Focal.trackOrientationChange(90);

6) Tracking scrolls

• Scrolling can either relate to the complete viewport (e.g. on a website) or relate to an element (e.g. a ScrollView or a textarea element)

Track scrolling related to an element (e.g. ScrollView in react native or textarea on a website)

• Track the current scroll position by using Focal.trackScrolling(Y_POSITION, X_POSITION, ELEMENT_NAME, ELEMENT_WIDTH, ELEMENT_HEIGHT, CONTENT_WIDTH, CONTENT_HEIGHT)
  • Y_POSITION / X_POSITION means the scroll position
  • ELEMENT_NAME can be any string, e.g. the CSS-ID of an element
  • ELEMENT_WIDTH / ELEMENT_HEIGHT is the dimension of the element that we are scrolling (comparable to INNER_WIDTH / INNER_HEIGHT, see viewport dimensions)
  • CONTENT_WIDTH / CONTENT_HEIGHT is the dimension of the element that we are scrolling (comparable to SCROLL_WIDTH / SCROLL_HEIGHT, see viewport dimensions)

Example integration: React native application

<ScrollView 
        onScroll={(event) => {
          const {contentOffset, contentSize, layoutMeasurement} = event.nativeEvent
          Focal.trackScrolling(contentOffset.y, contentOffset.x, 
                                 "yourScrollElement", 
                                 layoutMeasurement.width, layoutMeasurement.height, 
                                 contentSize.width, contentSize.height);
        }}
        scrollEventThrottle={100}>
        /* Your very long content */
</ScrollView>

Track scrolling related to the complete viewport (e.g. on a website)

• Track the current scroll position by using Focal.trackScrolling(Y_POSITION, X_POSITION)
  • X_POSITION is optional

Focal.trackScrolling(300);

• Note that you should set the SCROLL_WIDTH / SCROLL_HEIGHT and the INNER_WIDTH / INNER_HEIGHT dimension parameter before tracking a scroll, so that we are able to internally calculate and automatically track the visible percentage of the page length (percentage visible)

6) Tracking clicks

• use the function Focal.trackClick(X_POSITION, Y_POSITION, ELEMENT_NAME)
  • ELEMENT_NAME can be any string, e.g. the CSS-ID of an element

Example integration: React native application

<Button title="Press me" onPress={(e) => {
      Focal.track([
         createFocalClickEvent("PressMeButton",e.nativeEvent.pageX,e.nativeEvent.pageY)
      ])
}} />

7) Tracking custom variables and events

• Besides existing events such as views, scrolls or clicks, you can track custom events or variables, e.g. an additional user id, a login status or cart values.
• To do so, create a new custom variable in the Focal login area under Settings and specify a label for your variable.
• After that, call Focal.trackCustomVariable(LABEL, CONTENT)
• you can send any content that can be stringified as a JSON, e.g. a string or an object

Example integration

Focal.trackCustomVariable("cart", {value:15, items: [900, 313]});

8) Tracking app states

• Focal currently supports to track the app states ACTIVE(1) and BACKGROUND(0)
• On a website this maps to the window's focus and blur events

Example integration: React native application

import { AppState } from 'react-native';
AppState.addEventListener('change', (nextAppState) => {
    if(nextAppState == "active"){
       Focal.trackAppState(1)
    }else{
       Focal.trackAppState(0);
    }
});

More examples

Initialize the tracking on a simple web aplication

const APP_ID=27;
const APP_TOKEN="TESTTOKEN";
const FocalWriteFunction = async (key, jsonObj) => {
  localStorage.setItem(key, JSON.stringify(jsonObj) );
}
const FocalReadFunction = async (key) => {
  const tmpObj = localStorage.getItem(key);
  if(tmpObj === null){
    return {}
  }else{
    return JSON.parse(tmpObj);
  }
} 
Focal.init (APP_ID,APP_TOKEN, FocalReadFunction, FocalWriteFunction, window.fetch.bind(window))

Using node-localstorage to replace local storage in node apps

• If you develop your app in node, you can use node-localstorage to replace the local storage functions:

Initialize the tracking on a simple web aplication

import { LocalStorage } from "node-localstorage";
import fetch from "node-fetch";
global.localStorage = new LocalStorage('./_scratch'); // LocalStorage constructor requires a folder for your storage

const FocalWriteFunction = async (key, jsonObj) => {
  localStorage.setItem(key, JSON.stringify(jsonObj) );
}
// ...