js array for loop performance compare All In One

js array for loop performance compare All In One

for...of, for...in, Array.map, Array.forEach, while

js Array for loop performance

// const boxes = [...``.padStart(10, ` `)].map((item, i) => ({}));
const boxes = [...``.padStart(1, ` `)].map((item, i) => ({}));
const creative_ids_map = [...``.padStart(1000000, ` `)].map((item, i) => ({
  creative_id: i + 1,
  creative_name: `${i + 1}`,
}));
const creative_boxes = [];

const start = new Date().getTime();
console.log("once_time", start);

boxes.forEach(item => {
  const creativeIds = [];
  const creativeIdsMap = [];
  // creative_ids_map 需要 for 循环一次  (代码行数多，循环次数少)
  for (const obj of creative_ids_map) {
      const {
          creative_id,
          creative_name,
      } = obj;
      creativeIds.push(creative_id);
      creativeIdsMap.push({
          creative_id,
          creative_name,
      });
  }
  creative_boxes.push({
      creative_ids: creativeIds,
      creative_ids_map: creativeIdsMap,
  });
});

const end = new Date().getTime();
console.log("once_time", end);
console.log("once cost time", (end - start));

// const boxes = [...``.padStart(10, ` `)].map((item, i) => ({}));
const boxes = [...``.padStart(1, ` `)].map((item, i) => ({}));
const creative_ids_map = [...``.padStart(1000000, ` `)].map((item, i) => ({
  creative_id: i + 1,
  creative_name: `${i + 1}`,
}));
const creative_boxes = [];

const start = new Date().getTime();
console.log("twice_time", start);

boxes.forEach(item => {
  // creative_ids_map 需要 for 循环两次 (代码行数少，循环次数多)
  const creativeIds = creative_ids_map.map(obj => obj.creative_id) || [];
  const creativeIdsMap = creative_ids_map.map(obj => ({
    creative_id: obj.creative_id,
    creative_name: obj. creative_name,
  })) || [];
  creative_boxes.push({
      creative_ids: creativeIds,
      creative_ids_map: creativeIdsMap,
  });
});

const end = new Date().getTime();
console.log("twice_time", end);
console.log("twice cost time", (end - start));

testing

https://levelup.gitconnected.com/which-is-faster-for-for-of-foreach-loops-in-javascript-18dbd9ffbca9

https://blog.bitsrc.io/measuring-performance-of-different-javascript-loop-types-c0e9b1d193ed

https://leanylabs.com/blog/js-forEach-map-reduce-vs-for-for_of/

refs

https://stackoverflow.com/questions/5349425/whats-the-fastest-way-to-loop-through-an-array-in-javascript
https://jsben.ch/wY5fo

https://alligator.io/js/foreach-vs-for-loops/

https://felixgerschau.com/foreach-vs-map-javascript/

https://blog.kuzzle.io/efficiently-iterate-on-javascript-arrays

https://www.freecodecamp.org/news/how-to-optimize-your-javascript-apps-using-loops-d5eade9ba89f/

https://www.section.io/engineering-education/javascript-iterations-which-one-is-faster/

https://javascript.plainenglish.io/which-type-of-loop-is-fastest-in-javascript-ec834a0f21b9

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