Creating a custom Twig filter
Similar to a Twig function used to extract or generate content, a Twig filter can be used to transform a value into something different.
We can use the same WeatherExtension class that we used before to add our custom functions, but this time we’ll implement the getFilters() method:
public function getFilters(): array {
return [
new TwigFilter(
'celsius_to_fahrenheit',
[$this, 'celsiusToFahrenheit']
),
];
}
Staying in the field of meteorology, we’ve implemented a Twig filter to convert a temperature value from Celsius to Fahrenheit. The code for the filter is a simple one-line method:
public function celsiusToFahrenheit(
float $celsius
): float {
return $celsius * 1.8 + 32;
}
WeatherExtension is already tagged to be a Twig extension (in the...