fold (method)

fold

• fold<R>(_someCase, noneCase): R

• Reduces the Opt instance to a single value by applying a function to the value inside Some or returning a default value for None.

  Type Parameters

  • R

  Parameters

  • _someCase: ((x) => R)

    Function to apply to the value inside Some.

    • • (x): R

      • Parameters

        • x: T

        Returns R

  • noneCase: R

    Default value to return for None.

  Returns R

  Example

  opt(1).fold(x => x + 1, 0) // 2
  none.fold(x => x + 1, 0) // 0