description

# compareByIndex<T extends Enum> static method

1. @Since.new("2.15")

int compareByIndex<T extends Enum>(

1. T value1,
2. T value2

)

Compares two enum values by their index.

A generic Comparator function for enum types which orders enum values by their index value, which corresponds to the source order of the enum element declarations in the `enum` declaration.

Example:

    enum Season { spring, summer, autumn, winter }

    void main() {
      var relationByIndex =
          Enum.compareByIndex(Season.spring, Season.summer); // < 0
      relationByIndex =
          Enum.compareByIndex(Season.summer, Season.spring); // > 0
      relationByIndex =
          Enum.compareByIndex(Season.spring, Season.winter); // < 0
      relationByIndex =
          Enum.compareByIndex(Season.winter, Season.spring); // > 0
    }

## Implementation

    @Since("2.15")
    static int compareByIndex<T extends Enum>(T value1, T value2) =>
        value1.index - value2.index;