It's the first attempt to test the performance of a function that given an array will return a certain value.

big-o-and-scalability.js

const nemo = ["nemo"];

function findNemo(array) {
  let t0 = performance.now();
  for (let i = 0; i < array.lenght; i++) {
    if (array[i] === "nemo") {
      console.log("Found NEMO!");
    }
  }
  let t1 = performance.now();

  console.log(`Call to find Nemo took ${t1 - t0} milliseconds`);
}

findNemo(nemo);