keyvalue pipe doesn't preserve a Map's sorted order

🐞 bug report

Affected Package

The issue is caused by package @angular/common

Is this a regression?

No

Description

One of the reasons a developer uses a Map over an Object is to have Object-like features with sorted keys. When passing a Map to *ngFor with the keyvalue pipe, the map's sorted order is lost.

The bug is that the keyvalue pipe uses the defaultComparator for Maps. No sorting should be applied when keyvalue is passed a Map.

🔬 Minimal Reproduction

https://stackblitz.com/edit/angular-keyvalue-pipe-map-order?file=src/app/app.component.ts

🌍 Your Environment

Angular Version:

8.0.2

[Drageaux]

@ravishivt Agree with you.

Although I don’t think it’s a bug if they’ve intended it that way, there should be an easy way to preserve the order. Why not leave it as is, then we can sort however we want right? Why apply the defaultComparator instead?

Say, my Map doesn’t follow any sorting algorithm, and I want to keep the structure. There’s not a way to revert back to that unsorted structure even with a custom comparatorFn

EDIT:

Actually I found a simple way to preserve the order

// *.component.ts
asIsOrder(a, b) {
  return 1;
}

<!-- *.component.html -->
<div
      *ngFor="
        let someVal of someMap | keyvalue: asIsOrder;
        let i = index
      ">
</div>

return 1 because a is the element that gets passed in first, and 1 means it should come first in the array

[djleonskennedy]

@radotzki Have you heard about map data structure before? Do not disgrace, close the ticket