angular keyvalue pipe sort properties / iterate in order angular keyvalue pipe sort properties / iterate in order angular angular

angular keyvalue pipe sort properties / iterate in order


According to the Angular documentation, the keyvalue pipe sorts the items by key order by default. You can provide a comparer function to change that order, and sort the items according to the key, to the value, or to the entry order of the properties in the object.

The following comparer functions sort the items in various orders:

// Preserve original property orderoriginalOrder = (a: KeyValue<number,string>, b: KeyValue<number,string>): number => {  return 0;}// Order by ascending property valuevalueAscOrder = (a: KeyValue<number,string>, b: KeyValue<number,string>): number => {  return a.value.localeCompare(b.value);}// Order by descending property keykeyDescOrder = (a: KeyValue<number,string>, b: KeyValue<number,string>): number => {  return a.key > b.key ? -1 : (b.key > a.key ? 1 : 0);}

when applied to the keyvalue pipe:

<div *ngFor="let item of object | keyvalue: originalOrder">  {{item.key}} : {{item.value}}</div><div *ngFor="let item of object | keyvalue: valueAscOrder">  {{item.key}} : {{item.value}}</div><div *ngFor="let item of object | keyvalue: keyDescOrder">  {{item.key}} : {{item.value}}</div>

See this stackblitz for a demo.


Supplying a constant or null instead of a valid comparer function preserves the entry order of the object properties, like originalOrder does, but it causes an exception (see this stackblitz):

<!-- The following syntaxes preserve the original property order --><div *ngFor="let item of object | keyvalue: 0"><div *ngFor="let item of object | keyvalue: 374"><div *ngFor="let item of object | keyvalue: null"><!-- but they cause an exception (visible in the console) -->ERROR TypeError: The comparison function must be either a function or undefined

Moreover, using that syntax twice in the template does not display the items at all. Therefore, I would not recommend it. Please note that supplying undefined as the comparer function does not cause any exception but does not change the default behavior: the items are sorted by key value.


<div *ngFor="let item of object | keyvalue: 0">  {{item.key}} : {{item.value}}</div>

directly write and you will get the data in sameorder as it is in the json

keyvalue: 0


Yes, by default the keyvalue pair sorting data in ascending order.

To keep it unsorted modify as:

keyvalue: 0

Final code:

<div *ngFor="let item of object | keyvalue:0">  {{item.key}}:{{item.value}}</div>

But for angular 7 or above, you need to put an empty function to keep data unsorted.

<div *ngFor="let item of object | keyvalue: unsorted">      {{item.key}}:{{item.value}}    </div>

In your .ts file just put this empty function.

  unsorted() { }

Hope it's helpful.