Rearrange object in an array JavaScript-CodePudding

I have PriorityArray as

[1, 2, 3]

and response json as

[ {
Id: 1,
Name:”aaa”,
Priority:1
},
{
Id: 2,
Name:”bbb”,
Priority:1
},
{
Id: 3,
Name:”ssss”,
Priority:2
},
{
Id: 4,
Name:”aaa”,
Priority:2
},
{
Id: 5,
Name:”dddd”,
Priority:1
},
{
Id: 6,
Name:”dddd”,
Priority:3
}]

I want to arrange all objects based on priority in rotation. Products should be arranged in an array like 1,2,3 then again append next products with priority 1,2,3

Expected output:

[ {
Id: 1,
Name:”aaa”,
Priority:1
},
{
Id: 3,
Name:”ssss”,
Priority:2
},
{
Id: 6,
Name:”dddd”,
Priority:3
}
{
Id: 2,
Name:”bbb”,
Priority:1
},
{
Id: 4,
Name:”aaa”,
Priority:2
},
{
Id: 5,
Name:”dddd”,
Priority:1
},
]

CodePudding user response：

Group the response objects by their priority.
Then find the group that has highest no. of items in it.
And then loop over the grouped array until all elements have been added to the final array.

const priority = [1, 2, 3];
const res = [
  { Id: 1, Name: "aaa", Priority: 1 },
  { Id: 2, Name: "bbb", Priority: 1 },
  { Id: 3, Name: "ssss", Priority: 2 },
  { Id: 4, Name: "aaa", Priority: 2 },
  { Id: 5, Name: "dddd", Priority: 1 },
  { Id: 6, Name: "dddd", Priority: 3 },
];

const resGroupedByPriority = priority.map((p) =>
  res.filter((r) => r.Priority === p)
);

let index = 0;
let maxIndex = Math.max(...resGroupedByPriority.map((p) => p.length));
let ordered = [];

while (index < maxIndex) {
  resGroupedByPriority.forEach((p) => {
    if (p[index]) {
      ordered.push(p[index]);
    }
  });
  index  = 1;
}
console.log(ordered);

CodePudding user response：

You can simply sort array by priority.

yourArray.sort((a, b) => a.Priority>b.Priority?1:-1);

CodePudding user response：

You could take an object for the indices and create a new array and filter it.

const
    order = [1, 2, 3],
    data = [{ Id: 1, Name: 'aaa', Priority: 1 }, { Id: 2, Name: 'bbb', Priority: 1 }, { Id: 3, Name: 'ssss', Priority: 2 }, { Id: 4, Name: 'aaa', Priority: 2 }, { Id: 5, Name: 'dddd', Priority: 1 }, { Id: 6, Name: 'dddd', Priority: 3 }],
    indices = Object.fromEntries(order.map((k, v) => [k, v])),
    result = data
        .reduce((r, o) => {
            r[indices[o.Priority]] = o;
            indices[o.Priority]  = order.length;
            return r;
        }, [])
        .filter(Boolean);

console.log(result);

.as-console-wrapper { max-height: 100% !important; top: 0; }

A different approach.

const
    order = [1, 2, 3],
    data = [{ Id: 1, Name: 'aaa', Priority: 1 }, { Id: 2, Name: 'bbb', Priority: 1 }, { Id: 3, Name: 'ssss', Priority: 2 }, { Id: 4, Name: 'aaa', Priority: 2 }, { Id: 5, Name: 'dddd', Priority: 1 }, { Id: 6, Name: 'dddd', Priority: 3 }],
    temp = data.reduce((r, o) => {
        (r[o.Priority] ??= []).push(o);
        return r;
    }, {}),
    result = [];

let i = 0, go = true;

while (go) {
    go = false;
    for (const k of order) {
        if (!temp[k].length) break;
        result.push(temp[k].shift());
        go ||= temp[k].length;
    }
}


console.log(result);

.as-console-wrapper { max-height: 100% !important; top: 0; }

CodePudding user response：

This is what I came up with, it's rather crude but works fine.

const testList = [
  { Id: 1, Name: "aaa", Priority: 1 },
  { Id: 2, Name: "bbb", Priority: 1 },
  { Id: 3, Name: "ssss", Priority: 2 },
  { Id: 4, Name: "aaa", Priority: 2 },
  { Id: 5, Name: "dddd", Priority: 1 },
  { Id: 6, Name: "dddd", Priority: 3 },
];

function prioritySort(arr, priority) {
  arr = arr.slice(); //copies the array

  let result = [];
  let p = priority[0];
  let c = 0;

  while (arr.length > 0 || c > 10000) {
    c  ;

    for (let curr in arr) {
      if (arr[curr].Priority == p) {
        result.push(arr[curr]);

        arr.splice(curr, 1);

        break;
      }
    }

    if (c == priority.length) {
      p = priority[0];
      c = 0;
    } else {
      p = priority[c];
    }
  }

  return result;
}

console.log(prioritySort(testList, [1, 2, 3]));