如何对这样格式化的数组进行排序？

Question

I was trying to sort an array like this by "walls":

[{
  "536606220753305611": { "walls": 4 },
  "137616812886982656": { "walls": 5 },
  "189862971520843776": { "walls": 4 },
  "230433188491558913": { "walls": 2 }
}]

I can't seem to access the array from within the ids with array.sort.

Here's what I've tried:

let top10 = array.sort(function(a,b){
  return a.walls.localeCompare(b.walls).slice(0, 10);
 });

It won't work here because I can't find how to get inside the id arrays.

I expect the result I logged to be in order, but it shows this instead:

[ { '536606220753305611': { walls: 4 },
    '137616812886982656': { walls: 5 },
    '189862971520843776': { walls: 4 },
    '230433188491558913': { walls: 2 } } ]

Thanks!

Codingpro

Answer 1

If the desired output is an object with ordered keys, that can't be done (JS objects' properties are inherently unordered). You can first transform the input into an array of objects, then sort those....

 let data = [{ "536606220753305611": { "walls": 4 }, "137616812886982656": { "walls": 5 }, "189862971520843776": { "walls": 4 }, "230433188491558913": { "walls": 2 } }] // transform the input object into an array of objects of the form: // // [ { "long string of digits" : { walls : 4 } }, // { "long string of digits" : { walls : 2 } }, // etc. // ] let data0 = data[0]; let objects = Object.keys(data0).map(k => { return { k: data0[k] } }); let sorted = objects.sort((a, b) => { let keyA = Object.keys(a)[0]; let keyB = Object.keys(b)[0]; return a[keyA].walls - b[keyB].walls; }); console.log(sorted) 

Answer 2

What you're trying to do isn't possible with your current data structure.

You basically have one element in your array that you're trying to sort... which by default is already sorted. And it isn't possible to sort the keys in an object as they do not have any specific order.

For your example to work, you need to create multiple elements in your your list to sort. Here is an example of what you could do.

 const data = [{ "536606220753305611": { "walls": 4 } }, { "137616812886982656": { "walls": 5 } }, { "189862971520843776": { "walls": 4 } }, { "230433188491558913": { "walls": 2 } }]; const res = data.sort((a,b)=>{ return Object.values(a).shift().walls - Object.values(b).shift().walls; }); console.log(res); 

Answer 3

Here you have another approach that use the experimental flatMap() and will also work if you have one initial array with multiple objects containing data:

 const input = [ { "536606220753305611": { "walls": 4 }, "137616812886982656": { "walls": 5 }, "189862971520843776": { "walls": 4 }, "230433188491558913": { "walls": 2 } }, { "336606220753305611": { "walls": 9 }, "437616812886982656": { "walls": 7 }, "789862971520843776": { "walls": 23 }, "90433188491558913": { "walls": 1 } } ]; let res = input.flatMap(e => Object.entries(e)) .sort((a, b) => a[1].walls - b[1].walls) .map(([key, value]) => ({[key]: value})); console.log(res); 

Answer 4

If you wanted to keep a similar structure but sort the keys/values you could always swap your array for a Map instead.

 const data = [{ "536606220753305611": { "walls": 4 }, "137616812886982656": { "walls": 5 }, "189862971520843776": { "walls": 4 }, "230433188491558913": { "walls": 2 } }]; // Create a new Map from your existing data const map = new Map(Object.entries(data[0])); // Create an array of Map entries sorted by wall value // and then create a new Map from that array const sortedMap = new Map([...map.entries()].sort((a, b) => { return a[1].walls < b[1].walls; })); // Voila, a sorted Map for (let [k, v] of sortedMap.entries()) { console.log(k, v); }