block1.js

import { PerformanceMetadataMarker } from "performance-mark-metadata";
const marker = new PerformanceMetadataMarker();
const metadata = {
    details: { key: "value" }
};
const markerName = "name";
// mark with metadata
marker.mark(markerName, metadata);
performance.getEntriesByName(markerName).forEach(entry => {
    // get metadata for entry
    const result = marker.getEntryMetadata(entry);
    /*
    {
        details: { key: "value" }
    };
    */
    assert.strictEqual(result, metadata, "should get same metadata");
});