Interface IOptionImplementation<IsTrue, SomeType>

isNone

Some(2).isNone // false
None<number>().isNone // true
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isSome

Some(2).isSome // true
None<number>().isSome // false
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and

• and<CompareType>(
      value: IOption<CompareType>,
  ): MappedType<
      IsTrue,
      IOption<CompareType>,
      IOptionImplementation<IsTrue, SomeType>,
  >

  Method to compare two Options with and operation

  Type Parameters

  • CompareType

  Parameters

  • value: IOption<CompareType>

    other Option to compare

  Returns MappedType<
      IsTrue,
      IOption<CompareType>,
      IOptionImplementation<IsTrue, SomeType>,
  >

  See

  https://doc.rust-lang.org/std/option/enum.Option.html#method.and

  Example

  Some(2).and(Some(3)) // Some(3)
  None().and(Some(3)) // None()
  Some(2).and(None()) // None()
  None().and(None()) // None()
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andThen

• andThen<CompareType, OverrideType = unknown>(
      callbackFunc: (
          value: MappedType<IsTrue, SomeType, OverrideType>,
      ) => IOption<CompareType>,
  ): MappedType<
      IsTrue,
      IOption<CompareType>,
      IOptionImplementation<IsTrue, SomeType>,
  >

  Method to compare two Options with andThen operation

  Type Parameters

  • CompareType
  • OverrideType = unknown

  Parameters

  • callbackFunc: (value: MappedType<IsTrue, SomeType, OverrideType>) => IOption<CompareType>

    function to return default value

  Returns MappedType<
      IsTrue,
      IOption<CompareType>,
      IOptionImplementation<IsTrue, SomeType>,
  >

  See

  https://doc.rust-lang.org/std/option/enum.Option.html#method.and_then

  Example

  Some(2).andThen((val) => Some(val + 1)) // Some(3)
  None().andThen<number>((val) => Some(val + 1)) // None()
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cloned

• cloned(): IOptionImplementation<IsTrue, SomeType>

  Method to clone an Option

  Returns IOptionImplementation<IsTrue, SomeType>

  • cloned Option instance

  Example

  const x = Some(2);
  const y = x.clone();
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eq

• eq(other: IOption): boolean

  Compare two Options

  Parameters

  • other: IOption

  Returns boolean

expect

• expect(error: string | Error): MappedType<IsTrue, SomeType, never>

  expect the Option to be Some or throw an error

  Parameters

  • error: string | Error

  Returns MappedType<IsTrue, SomeType, never>

  Example

  Some(2).expect('error message') // 2
  None().expect('error message') // throws new Error('error message')
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getOrInsert

• getOrInsert(value: SomeType): SomeType

  Method to get the value or insert a new value

  Parameters

  • value: SomeType

    value to insert if None

  Returns SomeType

  See

  https://doc.rust-lang.org/std/option/enum.Option.html#method.get_or_insert

  Example

  Some(2).getOrInsert(3) // 2
  None().getOrInsert(3) // 3
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insert

• insert(value: SomeType): SomeType

  Inserts value into Option.

  Parameters

  • value: SomeType

    new value

  Returns SomeType

  currently set value

  See

  https://doc.rust-lang.org/std/option/enum.Option.html#method.insert

map

• map<NewType>(
      fn: (value: SomeType) => NewType,
  ): MappedType<
      IsTrue,
      IOptionImplementation<true, NewType>,
      IOptionImplementation<false, NewType>,
  >

  Map the Option value to a new value if Some

  Type Parameters

  • NewType

  Parameters

  • fn: (value: SomeType) => NewType

  Returns MappedType<
      IsTrue,
      IOptionImplementation<true, NewType>,
      IOptionImplementation<false, NewType>,
  >

  Example

  Some("text").map((v)=> Buffer.from(v)) // Some<Buffer>
  None<string>().map((v)=> Buffer.from(v)) // None<Buffer>
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  Since

  v1.0.4

match

• match<Output>(
      solver: OptionMatchSolver<SomeType, Output>,
      defaultValue?: Output,
  ): undefined | Output

  Match the Option value with a solver

  Type Parameters

  • Output

  Parameters

  • solver: OptionMatchSolver<SomeType, Output>

    solver to match the value (Map key to match, callback as resolver)
  • OptionaldefaultValue: Output

    default value if no match

  Returns undefined | Output

  See

  https://doc.rust-lang.org/std/option/enum.Option.html#method.match

  Example

  Some(1).match(
    new Map([
      [1, () => 'one'],
      [2, () => 'two'],
    ]),
    'other', // default value
  ); // 'one'
  None().match(
    new Map([
      [1, () => 'one'],
      [2, () => 'two'],
    ]),
    'other', // default value
  ); // 'other'
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• match<Output>(
      solver: OptionMatchSolver<SomeType, Output>,
      defaultValue: Output,
  ): Output

  Type Parameters

  • Output

  Parameters

  • solver: OptionMatchSolver<SomeType, Output>
  • defaultValue: Output

  Returns Output

or

• or<ValueType>(
      value: IOption<ValueType>,
  ): MappedType<
      IsTrue,
      IOptionImplementation<IsTrue, SomeType>,
      IOption<ValueType>,
  >

  Method to compare two Options with or operation

  Type Parameters

  • ValueType

  Parameters

  • value: IOption<ValueType>

    other Option to compare

  Returns MappedType<IsTrue, IOptionImplementation<IsTrue, SomeType>, IOption<ValueType>>

  See

  https://doc.rust-lang.org/std/option/enum.Option.html#method.or

  Example

  Some(2).or(Some(3)) // Some(2)
  None().or(Some(3)) // Some(3)
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orElse

• orElse<ValueType>(
      callbackFunc: (value: SomeType) => IOption<ValueType>,
  ): MappedType<
      IsTrue,
      IOptionImplementation<IsTrue, SomeType>,
      IOption<ValueType>,
  >

  Method to compare two Options with or operation

  Type Parameters

  • ValueType

  Parameters

  • callbackFunc: (value: SomeType) => IOption<ValueType>

    function to return default value

  Returns MappedType<IsTrue, IOptionImplementation<IsTrue, SomeType>, IOption<ValueType>>

  See

  https://doc.rust-lang.org/std/option/enum.Option.html#method.or_else

  Example

  Some(2).orElse(() => Some(3)) // Some(2)
  None().orElse(() => Some(3)) // Some(3)
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replace

• replace(value: SomeType): IOptionImplementation<IsTrue, SomeType>

  Replace the actual value with the given one and returns the old Option.

  Warning: currently TS can't change type of "this" (with asserts) and return value at the same time. https://github.com/microsoft/TypeScript/issues/41339

  Parameters

  • value: SomeType

    new value

  Returns IOptionImplementation<IsTrue, SomeType>

  old Option

  See

  https://doc.rust-lang.org/std/option/enum.Option.html#method.replace

take

• take(): IOptionImplementation<IsTrue, undefined | SomeType>

  Returns the contained Some value, consuming the self value.

  Warning: currently TS can't change type of "this" (with asserts) and return value at the same time. https://github.com/microsoft/TypeScript/issues/41339

  Returns IOptionImplementation<IsTrue, undefined | SomeType>

  copy of original Option

  Example

  const x = Some(2);
  const y = x.take();
  console.log(x.isNone); // true
  console.log(y.isSome); // true
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toJSON

• toJSON(): MappedType<IsTrue, IJsonSome<SomeType>, IJsonNone>

  Convert Option to JSON

  Returns MappedType<IsTrue, IJsonSome<SomeType>, IJsonNone>

  JSON

  Example

  Some(2).toJSON() // {$class: 'Option::Some', value: 2}
  None().toJSON() // {$class: 'Option::None'}
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toResult

• toResult<ErrType>(
      err: ErrType,
  ): MappedType<IsTrue, IOk<SomeType>, IErr<ErrType>>

  Convert Option to Result and discard the error type

  Type Parameters

  • ErrType

  Parameters

  • err: ErrType

  Returns MappedType<IsTrue, IOk<SomeType>, IErr<ErrType>>

  Result

  Example

  Some(2).toResult() // Ok<number>(2)
  None().toResult() // Err<never>()
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toString

• toString(): MappedType<IsTrue, `Some(${string})`, "None()">

  Convert Option to string

  Returns MappedType<IsTrue, `Some(${string})`, "None()">

  string representation of the Option

  Example

  Some(2).toString() // 'Some(2)'
  None().toString() // 'None()'
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unwrap

• unwrap(
      err?: Error | ((err: Error) => Error),
  ): MappedType<IsTrue, SomeType, never>

  Method to unwrap the value or throw an error if None

  Parameters

  • Optionalerr: Error | ((err: Error) => Error)

    optional error or function to transform the error

  Returns MappedType<IsTrue, SomeType, never>

  See

  https://doc.rust-lang.org/std/option/enum.Option.html#method.unwrap

  Example

  Some(2).unwrap() // 2
  None<number>().unwrap() // throws Error
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unwrapOr

• unwrapOr<DefType>(defaultValue: DefType): MappedType<IsTrue, SomeType, DefType>

  Method to unwrap the value or if None then return the default value.

  Type Parameters

  • DefType

  Parameters

  • defaultValue: DefType

    default value to return

  Returns MappedType<IsTrue, SomeType, DefType>

  See

  https://doc.rust-lang.org/std/option/enum.Option.html#method.unwrap_or

  Example

  Some(2).unwrapOr(3) // 2
  None<number>().unwrapOr(3) // 3
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unwrapOrElse

• unwrapOrElse<DefType>(fn: () => DefType): MappedType<IsTrue, SomeType, DefType>

  Method to unwrap the value or if None then return the default value from function.

  Type Parameters

  • DefType

  Parameters

  • fn: () => DefType

    function to return default value

  Returns MappedType<IsTrue, SomeType, DefType>

  See

  https://doc.rust-lang.org/std/option/enum.Option.html#method.unwrap_or_else

  Example

  Some(2).unwrapOrElse(() => 3) // 2
  None<number>().unwrapOrElse(() => 3) // 3
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unwrapOrValueOf

• unwrapOrValueOf<DefType>(
      BaseConstructor: ConstructorWithValueOf<DefType>,
  ): MappedType<IsTrue, SomeType, DefType>

  Method to unwrap the value or if None then return the default value from constructors valueOf (mimic Rust unwrap_or_default).

  Type Parameters

  • DefType

  Parameters

  • BaseConstructor: ConstructorWithValueOf<DefType>

    constructor to return default value from valueOf

  Returns MappedType<IsTrue, SomeType, DefType>

  See

  https://doc.rust-lang.org/std/option/enum.Option.html#method.unwrap_or_default

  Example

  Some(2).unwrapOrValueOf(Number) // 2
  None<number>().unwrapOrValueOf(Number) // 0
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