let arr = [];

resetArray = () => {
  arr = [];
  for (let i = 0; i < 1000; i++) {
    arr.push({
      item_metadata: {
        tags: [
          'tag1',
          'tag2',
          'tag3',
          'tag4',
          'tag5',
          'tag6',
          'tag7',
          'tag8',
          'tag9',
          'tag10',
        ],
      },
    });
  }
}

const foreachWay = () => {
  arr.forEach((el) => {
    el.item_metadata.tags.forEach((e) => {
      e = '';
    });
  });
};

const forWay = () => {
  for (let i = 0; i < arr.length; i++) {
    for (let j = 0; j < arr[i].item_metadata.tags.length; j++) {
      arr[i].item_metadata.tags[j] = '';
    }
  }
}


function benchmarkFunction(func, args, iterations = 100) {
  console.log('populating data...')
  resetArray();

  console.log(`benchmarking(${func.name}, iterations: ${iterations})`);
  console.log('\twarming up');
  // Warm-up run
  for (let i = 0; i < 10; i++) {
    // @ts-expect-error unknown
    func(...args);
  }

  console.log('\tbenchmarking');
  const start = performance.now();
  for (let i = 0; i < iterations; i++) {
    // @ts-expect-error unknown
    func(...args);
  }
  const end = performance.now();
  console.log('\tfinished !\n');
  return end - start;
}

const iterations = 10;


console.log('Benchmarking foreachWay');
const time1 = benchmarkFunction(foreachWay, [], iterations);
console.log('Benchmarking forWay');
const time2 = benchmarkFunction(forWay, [], iterations);

console.log(`foreachWay: ${time1}ms`);
console.log(`forWay: ${time2}ms`);

// output:
/*
Benchmarking foreachWay
populating data...
benchmarking(foreachWay, iterations: 10)
        warming up
        benchmarking
        finished !

Benchmarking forWay
populating data...
benchmarking(forWay, iterations: 10)
        warming up
        benchmarking
        finished !

foreachWay: 0.07125000000000092ms
forWay: 0.23512500000000003ms
*/