Effect.fail

失敗するeffectを作成

code:ts

import { Effect, Random } from "effect"

class HttpError {

readonly _tag = "HttpError"

}

class ValidationError {

readonly _tag = "ValidationError"

}

// ┌─── Effect<string, HttpError | ValidationError, never>

// ▼

const program = Effect.gen(function* () {

// Generate two random numbers between 0 and 1

const n1 = yield* Random.next

const n2 = yield* Random.next

// Simulate an HTTP error

if (n1 < 0.5) {

yield* Effect.fail(new HttpError())

}

// Simulate a validation error

if (n2 < 0.5) {

yield* Effect.fail(new ValidationError())

}

return "some result"

})