EquivalenceTypeLambdaType lambda for Equivalence, used for higher-kinded type operations.
When to use
Use when you need to abstract over Equivalence in higher-kinded type code.
Details
- Enables
Equivalenceto work with the Effect type system's HKT infrastructure - Used internally for type-level computations and generic abstractions
Example (Type-level usage)
import type { Equivalence, HKT } from "effect"
// Used internally for type-level computations
type NumberEquivalence = HKT.Kind<
Equivalence.EquivalenceTypeLambda,
never,
never,
never,
number
>
// Equivalent to: Equivalence.Equivalence<number>Source effect/Equivalence.ts:953 lines
export interface EquivalenceTypeLambda extends TypeLambda {
readonly EquivalenceTypeLambda.type: Equivalence<this["Target"]>type: type Equivalence<in A> = (
self: A,
that: A
) => boolean
Represents an equivalence relation over type A.
When to use
Use as a type annotation when you accept or return an equivalence function.
Details
- Returns
boolean: true if values are equivalent, false otherwise
- Must satisfy reflexive, symmetric, and transitive properties
Example (Defining simple number equivalence)
import type { Equivalence } from "effect"
const numberEq: Equivalence.Equivalence<number> = (a, b) => a === b
console.log(numberEq(1, 1)) // true
console.log(numberEq(1, 2)) // false
Example (Defining custom object equivalence)
import type { Equivalence } from "effect"
interface Point {
x: number
y: number
}
const pointEq: Equivalence.Equivalence<Point> = (a, b) =>
a.x === b.x && a.y === b.y
console.log(pointEq({ x: 1, y: 2 }, { x: 1, y: 2 })) // true
Equivalence<this["Target"]>
}