typocomath/src/numbers/arithmetic.ts

import type {configDependency} from '../core/Config.js'
import type {Dependencies, Signature} from '../interfaces/type.js'
import {$reflect} from '../interfaces/type.js'

export const add =        (): Signature<'add',        number> => (a, b) => a + b
const unaMinus = (a: number) => -a
export const unaryMinus = (): Signature<'unaryMinus', number> => unaMinus
export const conj =       (): Signature<'conj',       number> => a => a
export const subtract =   (): Signature<'subtract',   number> => (a, b) => a - b
export const multiply =   (): Signature<'multiply',   number> => (a, b) => a * b
export const absquare =   (): Signature<'absquare',   number> => a => a * a
export const reciprocal = (): Signature<'reciprocal', number> => a => 1 / a
export const divide =     (): Signature<'divide',     number> => (a, b) => a / b

const basicSqrt = (a: number) => isNaN(a) ? NaN : Math.sqrt(a)
export const conservativeSqrt = (): Signature<'conservativeSqrt', number> =>
  basicSqrt

export const sqrt =
  (dep: configDependency
   & Dependencies<'complex', number>): Signature<'sqrt', number> => {
    if (dep.config.predictable || !dep.complex) {
      return basicSqrt
    }
    return a => {
      if (isNaN(a)) return NaN
      if (a >= 0) return Math.sqrt(a)
      return dep.complex(0, Math.sqrt(unaMinus(a)))
    }
   }

$reflect!([
  add, unaryMinus, conj, subtract, multiply, absquare, reciprocal, divide,
  conservativeSqrt, sqrt
])