@effect-ts/system/_src/Ord/operations.ts

Effect-TS is a zero dependency set of libraries to write highly productive, purely functional TypeScript at scale.

// ets_tracing: off

import type { Equal } from "../Equal/index.js"
import { makeEqual } from "../Equal/index.js"
import type { Ordering } from "../Ordering/index.js"
import type { ForcedTuple } from "../Utils/index.js"
import type { Ord } from "./definition.js"

/**
 * Creates Ord[A] from a compare function
 */
export function makeOrd<A>(compare: (x: A, y: A) => Ordering): Ord<A> {
  return {
    compare
  }
}

/**
 * Contramap Ord input
 */
export function contramap<A, B>(f: (b: B) => A): (fa: Ord<A>) => Ord<B> {
  return (fa) => contramap_(fa, f)
}

/**
 * Contramap Ord input
 */
export function contramap_<A, B>(fa: Ord<A>, f: (b: B) => A): Ord<B> {
  return makeOrd((x, y) => fa.compare(f(x), f(y)))
}

/**
 * Test whether one value is _strictly greater than_ another
 */
export function gt<A>(O: Ord<A>): (x: A, y: A) => boolean {
  return (x, y) => O.compare(x, y) === 1
}

/**
 * Test whether one value is _non-strictly less than_ another
 */
export function leq<A>(O: Ord<A>): (x: A, y: A) => boolean {
  return (x, y) => O.compare(x, y) !== 1
}

/**
 * Test whether one value is _strictly less than_ another
 */
export function lt<A>(O: Ord<A>): (x: A, y: A) => boolean {
  return (x, y) => O.compare(x, y) === -1
}

/**
 * Take the maximum of two values. If they are considered equal, the first argument is chosen
 */
export function max<A>(O: Ord<A>): (x: A, y: A) => A {
  return (x, y) => (O.compare(x, y) === -1 ? y : x)
}

/**
 * Take the minimum of two values. If they are considered equal, the first argument is chosen
 */
export function min<A>(O: Ord<A>): (x: A, y: A) => A {
  return (x, y) => (O.compare(x, y) === 1 ? y : x)
}

/**
 * Test whether a value is between a minimum and a maximum (inclusive)
 */
export function between<A>(O: Ord<A>): (low: A, hi: A) => (x: A) => boolean {
  const lessThanO = lt(O)
  const greaterThanO = gt(O)
  return (low, hi) => (x) => lessThanO(x, low) || greaterThanO(x, hi) ? false : true
}

/**
 * Clamp a value between a minimum and a maximum
 */
export function clamp<A>(O: Ord<A>): (low: A, hi: A) => (x: A) => A {
  const minO = min(O)
  const maxO = max(O)
  return (low, hi) => (x) => maxO(minO(x, hi), low)
}

/**
 * Get the dual of an Ord
 */
export function inverted<A>(O: Ord<A>) {
  return makeOrd<A>((x, y) => O.compare(y, x))
}

/**
 * Get an instance of Equal
 */
export function getEqual<A>(O: Ord<A>): Equal<A> {
  return makeEqual((x, y) => O.compare(x, y) === 0)
}

/**
 * Given a tuple of `Ord`s returns an `Ord` for the tuple
 */
export function tuple<T extends ReadonlyArray<Ord<any>>>(
  ...ords: T
): Ord<
  ForcedTuple<{
    [K in keyof T]: T[K] extends Ord<infer A> ? A : never
  }>
> {
  return makeOrd((x, y) => {
    let i = 0
    for (; i < ords.length - 1; i++) {
      const r = ords[i]!.compare(x.get(i), y.get(i))
      if (r !== 0) {
        return r
      }
    }
    return ords[i]!.compare(x.get(i), y.get(i))
  })
}