function captureNavigation()

in packages/rum-core/src/performance-monitoring/navigation/capture-navigation.js [38:136]
51 lines of code
11 McCabe index (conditional complexity)

function captureNavigation(transaction) {
  /**
   * Do not capture timing related information when the
   * flag is set to false, By default both page-load and route-change
   * transactions set this flag to true
   */
  if (!transaction.captureTimings) {
    /**
     * Make sure page load transactions always starts at 0 irrespective if we capture navigation metrics or not
     * otherwise we would be reporting different page load durations for sampled and unsampled transactions
     */
    if (transaction.type === PAGE_LOAD) {
      transaction._start = 0
    }

    return
  }

  /**
   * Both start and end threshold decides if a span must be
   * captured as part of the transaction
   */
  const trEnd = transaction._end
  /**
   * Page load is considered as hard navigation and we account
   * for few extra spans than soft navigations which
   * happens on single page applications
   */
  if (transaction.type === PAGE_LOAD) {
    /**
     * Adjust custom marks properly to fit in the transaction timeframe
     */
    if (transaction.marks && transaction.marks.custom) {
      const customMarks = transaction.marks.custom
      Object.keys(customMarks).forEach(key => {
        customMarks[key] += transaction._start
      })
    }
    /**
     * must be zero otherwise the calculated relative _start time would be wrong
     */
    const trStart = 0
    transaction._start = trStart

    const timings = PERF.timing
    const baseTime = isRedirectInfoAvailable(timings)
      ? timings.redirectStart // make sure navigation spans will show up after the Redirect span
      : timings.fetchStart

    createNavigationTimingSpans(timings, baseTime, trStart, trEnd).forEach(
      span => {
        span.traceId = transaction.traceId
        span.sampled = transaction.sampled
        if (span.pageResponse && transaction.options.pageLoadSpanId) {
          span.id = transaction.options.pageLoadSpanId
        }
        transaction.spans.push(span)
      }
    )


    /**
    * Set the parent id of the transaction to the page load parent ID.
    * This means that the backend transaction will be the parent of
    * the page load transaction, which is useful for e.g Synthetics.
    */

    if (transaction.options.pageLoadParentId) {
      transaction.parentId = transaction.options.pageLoadParentId
    }

    /**
     * Page load marks that are gathered from NavigationTiming API
     */
    transaction.addMarks(getPageLoadMarks(timings))
  }

  if (isPerfTimelineSupported()) {
    const trStart = transaction._start
    /**
     * Capture resource timing information as spans
     */
    const resourceEntries = PERF.getEntriesByType(RESOURCE)
    createResourceTimingSpans(
      resourceEntries,
      state.bootstrapTime,
      trStart,
      trEnd
    ).forEach(span => transaction.spans.push(span))

    /**
     * Capture user timing measures as spans
     */
    const userEntries = PERF.getEntriesByType(MEASURE)
    createUserTimingSpans(userEntries, trStart, trEnd).forEach(span =>
      transaction.spans.push(span)
    )
  }
}