CODEWITHSUNDEEP
javascriptarraysangularsortingmultidimensional-array
AngularM
AngularM

Reputation: 16638

In JavaScript how do I sort an array of arrays by asc / desc

Tech: Angular 7, AngularCli, JS and TS.

In Js how do I sort an array of arrays by asc and desc order

This is my example array:

this.tableRows = [
  [ 'zz', 'cc' ],
  [ 'aa', 'cc' ],
  [ 'uu', 'dd' ]
];

I want to sort the above by column position and asc / desc.

This is my HTML:

<tr ls-table-row class="child-row" *ngFor="let row of tableRows">
  <td ls-table-cell *ngFor="let cell of row">{{ cell }}</td>
</tr>

I will be passing in the @inputs of type and columnPosition like so:

  @Input() public sortByColumnPosiition = 1;
  @Input() public sortByType = 'asc';

These explain the column I want to sort and type explains the direction e.g. desc.

This is my current example for sorting:

  sortByColumnPosition = 0;
  sortByType = 0;

  public sortBy(data: Array<Array<any>>) {
    return [ ...data ].sort((a, b) => a[ this.sortByColumnPosition ].localeCompare(b[ this.sortByColumnPosition ]) * this.sortByType);
  }

Above is my current attempt - but only works for column 0 and not column 1

Upvotes: 2

Views: 1809

Answers (3)

Ashish Yadav
Ashish Yadav

Reputation: 3196

If you are using angular you can use pipes for sorting in asc/desc

import { Pipe, PipeTransform } from "@angular/core";
@Pipe({
  name: "sort"
})
export class ArraySortPipe  implements PipeTransform {
  transform(array: any, field: string): any[] {
    if (!Array.isArray(array)) {
      return;
    }
    function sortBy(arr, field){
     let type = 1;
     let col = 0;
     if(field == 'DESC'){
       type = -1;
       col = 0;
     }
     return [...arr].sort((a,b) => a[col].localeCompare(b[col]) * type)
    }
    sortBy(array,field)
   }
}


<tr ls-table-row class="child-row" *ngFor="let row of tableRows | sort:'ASC'>
 <td ls-table-cell *ngFor="let cell of row">{{ cell }}</td>
</tr>

Upvotes: 0

Kunal Mukherjee
Kunal Mukherjee

Reputation: 5853

You can use the .localeCompare() to check which string comes first in the order of sorting.

const tableRows = [
  [ 'zz', 'cc' ],
  [ 'aa', 'cc' ],
  [ 'uu', 'dd' ]
];

function sortAscending(arr) {
  // To avoid mutating the original array, make a deep copy
  const arrToSort = Array.from(arr);
  
  return arrToSort.sort(([a, b], [c, d]) => a.localeCompare(c) || b.localeCompare(d));
}

function sortDescending(arr) {
    // To avoid mutating the original array, make a deep copy
  const arrToSort = Array.from(arr);
  
  return arrToSort.sort(([a, b], [c, d]) => c.localeCompare(a) || d.localeCompare(b));
}

const sortedAscArr = sortAscending(tableRows);
const sortedDescArr = sortDescending(tableRows);

console.log(sortedAscArr);
console.log(sortedDescArr);

Upvotes: 0

Maheer Ali
Maheer Ali

Reputation: 36584

You can create a function which takes Array, column no and the sort order(asc/desc).

You can use a trick to use a same function for asc/desc sort. Have a variable whose value will be 1 or -1. Always multiply it with each result or sort() callback. If you will pass 1 it will sort asc and desc for -1

const tableRows = [
  ['zz', 'cc'],
  ['aa', 'cc'],
  ['uu', 'dd']
];

function sortBy(arr, col, type = 1) {
  return [...arr].sort((a, b) => a[col].localeCompare(b[col]) * type)
}

console.log(sortBy(tableRows, 1)) //asc
console.log(sortBy(tableRows, 0, -1)) //desc

Upvotes: 4

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