function _findPerfResourceEntry()

in extensions/applicationinsights-dependencies-js/src/ajax.ts [815:876]
48 lines of code
19 McCabe index (conditional complexity)

            function _findPerfResourceEntry(initiatorType:string, ajaxData:ajaxRecord, trackCallback:() => void, reportError:(e:any) => void): void {
                let perfMark = ajaxData.perfMark;
                let performance = getPerformance();

                let maxAttempts = _config.maxAjaxPerfLookupAttempts;
                let retryDelay = _config.ajaxPerfLookupDelay;
                let requestUrl = ajaxData.requestUrl;
                let attempt = 0;
                (function locateResourceTiming() {
                    try {
                        if (performance && perfMark) {
                            attempt++;
                            let perfTiming:PerformanceResourceTiming = null;
                            let entries = performance.getEntries();
                            for (let lp = entries.length - 1; lp >= 0; lp--) {
                                let entry:PerformanceEntry = entries[lp];
                                if (entry) {
                                    if (entry.entryType === "resource") {
                                        if ((entry as PerformanceResourceTiming).initiatorType === initiatorType &&
                                                (_indexOf(entry.name, requestUrl) !== -1 || _indexOf(requestUrl, entry.name) !== -1)) {

                                            perfTiming = entry as PerformanceResourceTiming;
                                        }
                                    } else if (entry.entryType === "mark" && entry.name === perfMark.name) {
                                        // We hit the start event
                                        ajaxData.perfTiming = perfTiming;
                                        break;
                                    }

                                    if (entry.startTime < perfMark.startTime - 1000) {
                                        // Fallback to try and reduce the time spent looking for the perf entry
                                        break;
                                    }
                                }
                            }
                        }

                        if (!perfMark ||                // - we don't have a perfMark or
                            ajaxData.perfTiming ||      // - we have not found the perf entry or
                            attempt >= maxAttempts ||   // - we have tried too many attempts or
                            ajaxData.async === false) { // - this is a sync request

                            if (perfMark && isFunction(performance.clearMarks)) {
                                // Remove the mark so we don't fill up the performance resources too much
                                performance.clearMarks(perfMark.name);
                            }

                            ajaxData.perfAttempts = attempt;

                            // just continue and report the track event
                            trackCallback();
                        } else {
                            // We need to wait for the browser to populate the window.performance entry
                            // This needs to be at least 1ms as waiting <= 1 (on firefox) is not enough time for fetch or xhr,
                            // this is a scheduling issue for the browser implementation
                            setTimeout(locateResourceTiming, retryDelay);
                        }
                    } catch (e) {
                        reportError(e);
                    }
                })();
            }