addMemoryEntry.ts

import { WINDOW } from '../constants';
import type { AddEventResult, MemoryData, ReplayContainer, ReplayPerformanceEntry } from '../types';
import { createPerformanceSpans } from './createPerformanceSpans';

type ReplayMemoryEntry = ReplayPerformanceEntry<MemoryData> & { data: { memory: MemoryInfo } };

interface MemoryInfo {
  jsHeapSizeLimit: number;
  totalJSHeapSize: number;
  usedJSHeapSize: number;
}

/**
 * Create a "span" for the total amount of memory being used by JS objects
 * (including v8 internal objects).
 */
export async function addMemoryEntry(replay: ReplayContainer): Promise<Array<AddEventResult | null>> {
  // window.performance.memory is a non-standard API and doesn't work on all browsers, so we try-catch this
  try {
    return Promise.all(
      createPerformanceSpans(replay, [
        // @ts-expect-error memory doesn't exist on type Performance as the API is non-standard (we check that it exists above)
        createMemoryEntry(WINDOW.performance.memory),
      ]),
    );
  } catch (error) {
    // Do nothing
    return [];
  }
}

function createMemoryEntry(memoryEntry: MemoryInfo): ReplayMemoryEntry {
  const { jsHeapSizeLimit, totalJSHeapSize, usedJSHeapSize } = memoryEntry;
  // we don't want to use `getAbsoluteTime` because it adds the event time to the
  // time origin, so we get the current timestamp instead
  const time = Date.now() / 1000;
  return {
    type: 'memory',
    name: 'memory',
    start: time,
    end: time,
    data: {
      memory: {
        jsHeapSizeLimit,
        totalJSHeapSize,
        usedJSHeapSize,
      },
    },
  };
}