Variable Mutation

Type Declaration

• flatMap: {
      <O, I2, O2, E2>(
          f: (o: O) => Mutation<I2, O2, E2>,
      ): <I, E>(self: Mutation<I, O, E>) => Mutation<I, O2, E2 | E>;
      <I, O, E, I2, O2, E2>(
          self: Mutation<I, O, E>,
          f: (o: O) => Mutation<I2, O2, E2>,
      ): Mutation<I, O2, E | E2>;
  }

  Chain mutations together, running the second after the first succeeds.

  Param: f

  Function that takes the first result and returns a new Mutation

  Example

  const createUser = yield* Mutation.make(createUserApi)
  const createAndVerify = createUser.pipe(
    Mutation.flatMap(user => verifyEmailMutation)
  )
  Copy

• isMutation: (value: unknown) => value is Mutation<unknown, unknown, unknown>

  Check if a value is a Mutation.

• make: <I, O, E = never, R = never>(
      execute: (input: I) => Effect<O, E, R>,
  ) => Effect<Mutation<I, O, E>, never, Scope | R>

  Create a Mutation from an Effect-returning execute function.

  Example

  const createUser = yield* Mutation.make((userData: CreateUserInput) =>
    Effect.gen(function* () {
      const response = yield* api.createUser(userData)
      return response.user
    })
  )
  
  const user = yield* createUser.run({ name: "Alice" })
  Copy

• map: {
      <O, O2>(
          f: (o: O) => O2,
      ): <I, E>(self: Mutation<I, O, E>) => Mutation<I, O2, E>;
      <I, O, E, O2>(self: Mutation<I, O, E>, f: (o: O) => O2): Mutation<I, O2, E>;
  }

  Map the successful data of a Mutation.

  Param: f

  Function to transform the data

  Example

  const createUser = yield* Mutation.make(createUserApi)
  const createUserName = createUser.pipe(Mutation.map(user => user.name))
  Copy

• MutationTypeId: symbol

• promise: <I, O>(
      execute: (input: I) => Promise<O>,
  ) => Effect<Mutation<I, O, never>, never, Scope>

  Create a Mutation from a Promise-returning function.

  Example

  const createUser = yield* Mutation.promise((userData: CreateUserInput) =>
    fetch('/api/users', {
      method: 'POST',
      body: JSON.stringify(userData)
    }).then(r => r.json())
  )
  Copy

• tryPromise: <I, O, E>(
      execute: (input: I) => Promise<O>,
      onError: (error: unknown) => E,
  ) => Effect<Mutation<I, O, E>, never, Scope>

  Create a Mutation from a Promise-returning function with error handling.

  Example

  const createUser = yield* Mutation.tryPromise(
    (userData: CreateUserInput) =>
      fetch('/api/users', {
        method: 'POST',
        body: JSON.stringify(userData)
      }).then(r => r.json()),
    (error) => new ApiError(error)
  )
  Copy