effect-io-ai

Package: effect
Module: Option

Option.bind

The “do simulation” in Effect allows you to write code in a more declarative style, similar to the “do notation” in other programming languages. It provides a way to define variables and perform operations on them using functions like bind and let.

Here’s how the do simulation works:

1. Start the do simulation using the Do value
2. Within the do simulation scope, you can use the bind function to define variables and bind them to Option values
3. You can accumulate multiple bind statements to define multiple variables within the scope
4. Inside the do simulation scope, you can also use the let function to define variables and bind them to simple values
5. Regular Option functions like map and filter can still be used within the do simulation. These functions will receive the accumulated variables as arguments within the scope

Example

import * as assert from "node:assert"
import { Option, pipe } from "effect"

const result = pipe(
  Option.Do,
  Option.bind("x", () => Option.some(2)),
  Option.bind("y", () => Option.some(3)),
  Option.let("sum", ({ x, y }) => x + y),
  Option.filter(({ x, y }) => x * y > 5)
)
assert.deepStrictEqual(result, Option.some({ x: 2, y: 3, sum: 5 }))

See

• Do
• bindTo
• let

Signature

declare const bind: { <N extends string, A extends object, B>(name: Exclude<N, keyof A>, f: (a: NoInfer<A>) => Option<B>): (self: Option<A>) => Option<{ [K in N | keyof A]: K extends keyof A ? A[K] : B; }>; <A extends object, N extends string, B>(self: Option<A>, name: Exclude<N, keyof A>, f: (a: NoInfer<A>) => Option<B>): Option<{ [K in N | keyof A]: K extends keyof A ? A[K] : B; }>; }

Source

Since v2.0.0