
By default, pipes are pure. This means that an instance of a pipe will be reused and the pipe will be called only when its arguments change. BREAKING CHANGE Before: @Pipe({name: 'date'}) class DatePipe {} defines an impure pipe. After: @Pipe({name: 'date'}) class DatePipe {} defines a pure pipe. @Pipe({name: 'date', pure: false}) class DatePipe {} defines an impure pipe. Closes #3966