@aller/blink/src/events/prepare-impression-event.ts

A library for tracking user behaviour.

import { calculateEventTime } from '../utils/event-time';
import generalData from '../utils/general-data';
import { BlinkEvent } from '../types';
import { Page } from '../selectors/get-page-state';

/**
 * Prepares a raw impression by aggregating its fields so that
 * it can be sent to the server in the format aas expects.
 */
export default function prepareArticleImpressionEvent(
  page: Page,
  id: string,
  time?: Date,
): BlinkEvent {
  const ap = page.state.articlePreview[id] || {
    id: id || 'error',
    url: undefined,
  };
  const inscreenTime = id
    ? calculateEventTime({
        times: page.state.inscreen[id],
        screenEvents: page.state.screen.events,
        now: time,
      })
    : 0;
  return {
    ...generalData(page.state),
    id: ap.id,
    context: ap.context || undefined,
    type: 'impression',
    inscreenTime,
    article: { url: ap.url, harvesterId: ap.id },
    title: ap.title || undefined,
    height: ap.height || 0,
    width: ap.width || 0,
    personalizationParametersRequested:
      ap.personalizationParametersRequested || undefined,
    personalizationSystemUsed: ap.personalizationSystemUsed || undefined,
    position: ap.position || undefined,
  };
}

export function getAllArticleImpressionEventsPrepared(
  page: Page,
  time?: Date,
): BlinkEvent[] {
  if (!page || !page.state) {
    return [];
  }
  return Object.keys(page.state.articlePreview)
    .map(articleId => {
      try {
        return prepareArticleImpressionEvent(page, articleId, time);
      } catch (err) {
        const event: BlinkEvent = { id: '', pageView: '', type: 'error' };
        return event;
      }
    })
    .filter(event => event.type !== 'error');
}