在 json object 和 javascript 和相应的索引或其他值中查找最大数字

Question

This javascript find the highest number but i want the corresponding id and index too, or the corresponding id.

const shots = [{
    id: 1,
    amount: 2
  },
  {
    id: 2,
    amount: 4
  },
  {
    id: 3,
    amount: 52
  },
  {
    id: 4,
    amount: 36
  },
  {
    id: 5,
    amount: 13
  },
  {
    id: 6,
    amount: 33
  }
];

var highest = shots.reduce((acc, shot) => acc = acc > shot.amount ? acc : shot.amount, 0);

OR

var highest = Math.max.apply(Math, shots.map(function(o) { return o.amount; }))

In this example the highest number is 52 then it mean that the corresponding index is 2. how to get this index value?

Finally, i need to get the corresponding id.

In real life, i should find the highest bitrate to get the corresponding highest quality video url.

Answer 1

Once you have the highest amount, you can .findIndex to get the object with that amount.

 const shots=[{id:1,amount:2},{id:2,amount:4},{id:3,amount:52},{id:4,amount:36},{id:5,amount:13},{id:6,amount:33}]; const highest = Math.max(...shots.map(o => o.amount)); const index = shots.findIndex(o => o.amount === highest); console.log(index, shots[index].id);

Or if you wanted to do it with just a single iteration

 const shots=[{id:1,amount:2},{id:2,amount:4},{id:3,amount:52},{id:4,amount:36},{id:5,amount:13},{id:6,amount:33}]; let index = 0; let best = -Infinity; shots.forEach((shot, i) => { if (shot.amount > best) { best = shot.amount; index = i; } }); console.log(index, shots[index].id);

If you only want the index to get to the ID, it's a bit easier.

 const shots=[{id:1,amount:2},{id:2,amount:4},{id:3,amount:52},{id:4,amount:36},{id:5,amount:13},{id:6,amount:33}]; const best = shots.reduce((a, b) => a.amount > b.amount? a: b); console.log(best);