effect-io-ai

Package: effect
Module: Result

Result.let

Adds a named field to the do-notation accumulator by computing a pure (non-Result) value from the current accumulated object.

When to use

Use when you need to add a derived field that cannot fail inside a do-notation pipeline.

Details

• Use bind when the computation returns a Result
• The field name must not collide with existing keys

Example (Adding a computed field)

import { pipe, Result } from "effect"

const result = pipe(
  Result.Do,
  Result.bind("x", () => Result.succeed(2)),
  Result.bind("y", () => Result.succeed(3)),
  Result.let("sum", ({ x, y }) => x + y)
)
console.log(result)
// Output: { _tag: "Success", success: { x: 2, y: 3, sum: 5 }, ... }

See

• Do to start the do-notation chain
• bind for Result-producing fields

Signature

declare const let: { <N extends string, R extends object, B>(name: Exclude<N, keyof R>, f: (r: NoInfer<R>) => B): <L>(self: Result<R, L>) => Result<{ [K in N | keyof R]: K extends keyof R ? R[K] : B; }, L>; <R extends object, L, N extends string, B>(self: Result<R, L>, name: Exclude<N, keyof R>, f: (r: NoInfer<R>) => B): Result<{ [K in N | keyof R]: K extends keyof R ? R[K] : B; }, L>; }

Source

Since v2.0.0