What Is Angular Impure Pipe?

What Is Impure Pipe?

Angular executes an impure pipe during every component change detection cycle. An impure pipe is called often, as often as every keystroke or mouse-move.

If you want to make a pipe impure that time you will allow the setting pure flag to false.

@Pipe({

  name: 'currency',

  pure:false

})

The example for impure pipe –

import { Pipe, PipeTransform } from '@angular/core';

@Pipe({

  name: 'currency',

  pure:false

})

export class CurrencyPipe implements PipeTransform {

  transform(value: any, args?: any): any {

    if (!value) {

      return '1.00';

    }

    return value;

  }

}

For more detail kindly refer the -
https://www.code-sample.com/2018/05/angular-5-6-7-pipes-decorator.html