angular-pipe

My problem is similar to this stackoverflow post When I use async pipe to observe data from firebase and show it in chart, I can see the chart but prompt null error in console. Without async pipe, all errors are gone but I can't fetch data (duh it's async data). Help me please. Cause This is happening because the component cannot work with null values for results . Why? Async pipe is, as you say, used when you do not want to (or do not need to) subscribe in the component code, but do it in the template instead. Pipe, however, is a pure function: is has to return something each time it's called

I have a list of emplyees and want to make a drop down with predefined department filter Im trying to make a filter pipe and pass a function as an arg it works only the first time its rendered but I want to invoke the pipe each time the user changes the selection Pipe: import { Pipe, PipeTransform, Injectable } from '@angular/core'; @Pipe({ name: 'filter' }) @Injectable() export class FilterPipe implements PipeTransform { transform(value: Array<any>, f) { return value.filter(x => f(x)); } } Component: constructor() { this.filterFunc = this.filterByDepatment.bind(this); } //filter function

<tr *ngFor="let a of arrayOfObjects"> <td *ngFor="let item of cfValues | keyvalue"> {{item.value}} </td> </tr> I am just trying to print the items in the regular order but the key/value pipe does a default sorting based on the index. Is there a way to disable the default sorting? You need to return 0 if you want them to not be ordered. So in your cause you could either do <td *ngFor="let item of cfValues | keyvalue : 0"> But that would throw a ts error: TypeError: The comparison function must be either a function or undefined Else, you can create a function that returns 0 and use function