measuringTcPrototype.js

const problemSize = 10000;
const g = n => n ** 2; // theoretical guess function
const timeRatios = [];
const m = 5; // from the O(g(n)) definition
const alpha = 1/127.372 // some suitable conversion constant
                        // depending on the CPUs number of
                        // instructions per second
let start = 0;

for (const n = m; i <= problemSize; n++) {
  try {
    start = performance.now();
    performanceSensitiveAlgorithm(n); // The code being analyzed
  } catch (error) {
    // Some appropriate error handling here...
  } finally {
    const measuredTime = performance.now() - start; // in ms
    const theoreticalTime = alpha * g(n) // now in ms
    timeRatios.push(theoreticalTime/measuredTime); // dimensionless
  }
}