What is the most efficient way to sort nested json by two fields?-CodePudding

Data Sample:

[{  'ID': objectID(dcdj12), 
    'Deprt': 'IT',
    'Employees': [ { 'ID': 3, 'StrtDT': '24-12-2022T08:30', 'flag': true },          
                   { 'ID': 2, 'StrtDT': '14-11-2021T08:30'  'flag': true },
                   { 'ID': 1, 'StrtDT': '22-11-2020T08:30', 'flag': false }]
  },
  { 'ID': objectID(dcdj132),
    'Deprt': 'HR',
    'Employees': [ { 'ID': 33, 'StrtDT': '24-12-2022T08:30', 'flag': false},          
                   { 'ID': 22, 'StrtDT': '14-11-2021T08:30'  'flag': true },
                   { 'ID': 11, 'StrtDT': '22-11-2020T08:30', 'flag': false }]
  },
  {  'ID': objectID(dcdj1321),'Deprt' : 'AC', 'Employees': []}... more thn 1000 ]

HTML code to show in table:

<tbody>
   <ng-container *ngFor="let D of Deprt">
     <tr *ngFor="let Emp of D.Employees" >
       <td> {{D.Deprt}} </td>
       <td> {{Emp.ID}}   </td>
       <td> {{Emp.StrtDT}}  </td>
       <td> {{Emp.flag}}  </td>
    </tr>
   </ng-container>
</tbody>

Current Output:

Deprt      ID        StrtDT        flag
IT         3     24-12-2022T08:30  true
IT         2     14-11-2021T08:30  true
IT         1     22-11-2020T08:30  false
HR         33    24-12-2022T08:30  false
HR         22    14-11-2021T08:30  true
HR         11    22-11-2020T08:30  false

Expected Output:

Deprt      ID        StrtDT        flag
IT         3     24-12-2022T08:30  true
IT         2     14-11-2021T08:30  true
HR         22     14-11-2021T08:30  true
HR         33     24-12-2022T08:30  false
IT         1     22-11-2020T08:30  false 
HR         11     22-11-2020T08:30  false

Tried:

this.data.forEach(x=>{
        console.log('c??',x)
        x.Employees.sort((a:any,b:any)=>{ return a.StrtDT- b.StrtDT})})

Here I am looking for to sort first by flag and then by dates recent to old.

even, would like to consider any different approach to get desire output.

CodePudding user response：

Since you want to sort across departments, you can't use the original data. Get a flat array of employees with a Deprt property.

data.flatMap(({ Deprt, Employees }) => 
  Employees.map(emp => ({ ...emp, Deprt, StartDate: getDate(emp.StrtDT) }))
)

Also, you need to add another property called StartDate. Your current format cannot be converted to a Date directly. So, you need to use regex to get each date time parts and convert it to Date

function getDate(dateStr) {
  const [d, m, y, h, min] = dateStr.match(/\d /g)
  return new Date(y, m-1, d, h, min)
}

And then sort firstly based on the flag and then by StartDate

array.sort((a, b) => b.flag - a.flag 
    || b.StartDate - a.StartDate
)

Here's a snippet:

const data = [
  {
    Deprt: 'IT',
    Employees: [
      { ID: 3, StrtDT: '24-12-2022T08:30', flag: true },
      { ID: 2, StrtDT: '14-11-2021T08:30', flag: true },
      { ID: 1, StrtDT: '22-11-2020T08:30', flag: false },
    ],
  },
  {
    Deprt: 'HR',
    Employees: [
      { ID: 33, StrtDT: '24-12-2022T08:30', flag: false },
      { ID: 22, StrtDT: '14-11-2021T08:30', flag: true },
      { ID: 11, StrtDT: '22-11-2020T08:30', flag: false },
    ],
  },
];

function getDate(dateStr) {
  const [d, m, y, h, min] = dateStr.match(/\d /g)
  return new Date(y, m-1, d, h, min)
}

const expected =
  data.flatMap(({ Deprt, Employees}) =>
    Employees.map(emp => ({ ...emp, Deprt, StartDate: getDate(emp.StrtDT) }))
  )
  .sort((a, b) => b.flag - a.flag 
  || b.StartDate - a.StartDate
  )

console.log(expected)

CodePudding user response：

Sort array by multiple fields, compare flags, if they are the same parse dates and compare them:

Update: you need to extend emloyees array with department info. Then flatten array to get array of employees and then sort it.

let arr = [{  'Deprt': 'IT',
       'Employees': [ { 'ID': 3, 'StrtDT': '24-12-2022T08:30', 'flag': true },
           { 'ID': 2, 'StrtDT': '14-11-2021T08:30' , 'flag': true },
           { 'ID': 1, 'StrtDT': '22-11-2020T08:30', 'flag': false }]
   },
       {  'Deprt': 'HR',
           'Employees': [ { 'ID': 33, 'StrtDT': '24-12-2022T08:30', 'flag': false},
               { 'ID': 22, 'StrtDT': '14-11-2021T08:30',  'flag': true },
               { 'ID': 11, 'StrtDT': '22-11-2020T08:30', 'flag': false }]
       },
       {  'Deprt' : 'AC', 'Employees': []} ];

  arr.forEach(o => o.Employees.forEach(e => e.Deprt = o.Deprt));
  arr = arr.flatMap(o => o.Employees);
  
   arr.sort( (a,b) => {
       if(a.flag !== b.flag) {
           return a.flag ? -1 : 1;
       } else {
           let [d,mon,y,h,min] = a.StrtDT.split(/\D/);
           const d1 = new Date(y, mon-1, d, h, min);

           [d,mon,y,h,min] = b.StrtDT.split(/\D/);
           const d2 = new Date(y, mon-1, d, h, min);

           return d2-d1;
       }
   } );


  console.log(arr);