检查列表中键最多的对象的最佳方法是什么？

Question

I have a list that has objects with a varying amount of keys. I want to make sure that I get the index from the list of the object with the most keys OR the reference to the object itself. What is the best way to do this?

My current approach is:

let index = -1;
let numKeys = 0;
for(var i = 0; i < mylistofobjects.length; i++) { 
  if(Object.keys(mylistofobjects[i]).length > numKeys) {
    index = i;
  }
}

// by the end, index has the most keys

Is there a smarter/shorter way to do this that would require less code in this day and age? If the way to get the object reference is shorter than the way to get the index number.. I would prefer the object reference.

Answer 1

One option is to reduce , keeping in the accumulator the object with the most keys found so far:

const objWithMostKeys = mylistofobjects.reduce((bestSoFar, thisObj) => (
  Object.keys(bestSoFar).length >= Object.keys(thisObj).length ? bestSoFar : thisObj
));

It's not entirely efficient because it checks the accumulator's number of keys on every iteration, rather than caching it, but caching it will require a bit more code:

let maxKeyCount = Object.keys(mylistofobjects[0]).length;
const objWithMostKeys = mylistofobjects.reduce((bestSoFar, currObj) => {
  const currKeyCount = Object.keys(currObj).length;
  if (currKeyCount > maxKeyCount) {
    maxKeyCount = currKeyCount;
    return currObj;
  }
  return bestSoFar;
});

This assumes that the mylistofobjects isn't empty. If that's a possibility, probably add a .length check beforehand, and return early / throw an error (or whatever you need to do) instead of proceeding.