880 lines
22 KiB
TypeScript
880 lines
22 KiB
TypeScript
/**
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* Works with TypeScript `number` values.
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*
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* This module exposes the native `Number` constructor together with helpers for
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* checking, parsing, arithmetic, safe division, comparison, range checks,
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* clamping, rounding, ordering, equivalence, and numeric aggregation.
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*
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* @since 2.0.0
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*/
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import * as Equ from "./Equivalence.ts"
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import { dual } from "./Function.ts"
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import * as Option from "./Option.ts"
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import * as order from "./Order.ts"
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import type { Ordering } from "./Ordering.ts"
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import * as predicate from "./Predicate.ts"
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import * as Reducer from "./Reducer.ts"
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/**
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* Exposes the global number constructor.
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*
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* **When to use**
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*
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* Use to access native JavaScript numeric coercion from the Effect module
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* namespace.
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*
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* **Gotchas**
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*
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* This follows native `Number` coercion rules, including empty strings
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* becoming `0` and invalid numeric strings becoming `NaN`.
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*
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* @see {@link parse} for parsing strings into an `Option`
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*
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* **Example** (Coercing values to numbers)
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*
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* ```ts
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* import { Number as N } from "effect"
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*
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* const num = N.Number("42")
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* console.log(num) // 42
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*
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* const float = N.Number("3.14")
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* console.log(float) // 3.14
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* ```
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*
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* @category constructors
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* @since 4.0.0
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*/
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export const Number = globalThis.Number
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/**
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* Checks whether a value is a `number`.
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*
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* **When to use**
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*
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* Use to validate unknown input and narrow it to `number`.
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*
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* **Example** (Checking for numbers)
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*
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* ```ts
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* import { Number } from "effect"
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* import * as assert from "node:assert"
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*
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* assert.deepStrictEqual(Number.isNumber(2), true)
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* assert.deepStrictEqual(Number.isNumber("2"), false)
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* ```
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*
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* @category guards
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* @since 2.0.0
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*/
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export const isNumber: (input: unknown) => input is number = predicate.isNumber
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/**
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* Provides an addition operation on `number`s.
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*
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* **When to use**
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*
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* Use to add two numbers.
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*
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* **Example** (Adding numbers)
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*
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* ```ts
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* import { Number } from "effect"
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* import * as assert from "node:assert"
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*
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* assert.deepStrictEqual(Number.sum(2, 3), 5)
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* ```
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*
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* @see {@link sumAll} for summing an iterable of numbers
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*
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* @category math
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* @since 2.0.0
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*/
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export const sum: {
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(that: number): (self: number) => number
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(self: number, that: number): number
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} = dual(2, (self: number, that: number): number => self + that)
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/**
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* Provides a multiplication operation on `number`s.
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*
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* **When to use**
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*
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* Use to multiply two numbers.
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*
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* **Example** (Multiplying numbers)
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*
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* ```ts
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* import { Number } from "effect"
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* import * as assert from "node:assert"
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*
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* assert.deepStrictEqual(Number.multiply(2, 3), 6)
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* ```
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*
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* @see {@link multiplyAll} for multiplying an iterable of numbers
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*
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* @category math
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* @since 2.0.0
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*/
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export const multiply: {
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(that: number): (self: number) => number
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(self: number, that: number): number
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} = dual(2, (self: number, that: number): number => self * that)
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/**
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* Provides a subtraction operation on `number`s.
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*
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* **When to use**
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*
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* Use to subtract one number from another.
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*
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* **Example** (Subtracting numbers)
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*
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* ```ts
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* import { Number } from "effect"
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* import * as assert from "node:assert"
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*
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* assert.deepStrictEqual(Number.subtract(2, 3), -1)
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* ```
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*
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* @category math
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* @since 2.0.0
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*/
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export const subtract: {
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(that: number): (self: number) => number
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(self: number, that: number): number
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} = dual(2, (self: number, that: number): number => self - that)
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/**
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* Divides `number`s safely, returning `Option.none()` if the divisor is `0`.
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*
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* **When to use**
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*
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* Use to divide numbers while representing division by zero as `Option.none`.
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*
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* **Example** (Dividing numbers safely)
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*
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* ```ts
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* import { Number } from "effect"
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*
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* Number.divide(6, 3) // Option.some(2)
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* Number.divide(6, 0) // Option.none()
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* ```
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*
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* @see {@link divideUnsafe} for division that throws when the divisor is zero
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* @see {@link remainder} for the numeric remainder operation
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*
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* @category math
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* @since 2.0.0
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*/
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export const divide: {
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(that: number): (self: number) => Option.Option<number>
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(self: number, that: number): Option.Option<number>
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} = dual(
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2,
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(self: number, that: number): Option.Option<number> => that === 0 ? Option.none() : Option.some(self / that)
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)
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/**
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* Divides two `number` values without returning an `Option`.
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*
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* **When to use**
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*
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* Use to divide `number` values where the divisor is known to be non-zero and
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* a plain `number` result is preferred over handling `Option.none`.
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*
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* **Gotchas**
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*
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* Throws a `RangeError` if the divisor is `0`.
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*
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* **Example** (Dividing numbers unsafely)
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*
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* ```ts
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* import { Number } from "effect"
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*
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* console.log(Number.divideUnsafe(6, 3)) // 2
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*
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* // Passing 0 as the divisor throws a RangeError("Division by zero").
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* ```
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*
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* @see {@link divide} for division that returns `Option.none` when the divisor is zero
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*
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* @category math
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* @since 4.0.0
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*/
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export const divideUnsafe: {
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(that: number): (self: number) => number
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(self: number, that: number): number
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} = dual(
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2,
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(self: number, that: number): number =>
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Option.getOrThrowWith(divide(self, that), () => new RangeError("Division by zero"))
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)
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/**
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* Returns the result of adding `1` to a given number.
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*
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* **When to use**
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*
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* Use to increment a numeric counter by one.
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*
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* **Example** (Incrementing a number)
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*
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* ```ts
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* import { Number } from "effect"
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* import * as assert from "node:assert"
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*
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* assert.deepStrictEqual(Number.increment(2), 3)
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* ```
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*
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* @category math
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* @since 2.0.0
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*/
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export const increment = (n: number): number => n + 1
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/**
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* Decrements a number by `1`.
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*
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* **When to use**
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*
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* Use to decrement a numeric counter by one.
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*
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* **Example** (Decrementing a number)
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*
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* ```ts
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* import { Number } from "effect"
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* import * as assert from "node:assert"
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*
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* assert.deepStrictEqual(Number.decrement(3), 2)
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* ```
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*
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* @category math
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* @since 2.0.0
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*/
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export const decrement = (n: number): number => n - 1
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/**
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* Order instance for `number` values.
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*
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* **When to use**
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*
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* Use when you need to sort or compare numbers through APIs that accept an
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* ordering instance.
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*
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* **Example** (Comparing numbers)
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*
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* ```ts
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* import { Number } from "effect"
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*
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* console.log(Number.Order(1, 2)) // -1
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* console.log(Number.Order(2, 1)) // 1
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* console.log(Number.Order(1, 1)) // 0
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* ```
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*
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* @category instances
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* @since 2.0.0
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*/
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export const Order: order.Order<number> = order.Number
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/**
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* Equivalence instance for numbers where `NaN` is considered equal to `NaN`.
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*
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* **When to use**
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*
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* Use when checking numeric equality through APIs that accept an equivalence
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* relation.
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*
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* **Example** (Comparing numbers for equivalence)
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*
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* ```ts
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* import { Number } from "effect"
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*
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* console.log(Number.Equivalence(1, 1)) // true
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* console.log(Number.Equivalence(1, 2)) // false
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* console.log(Number.Equivalence(NaN, NaN)) // true
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* ```
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*
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* @category instances
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* @since 2.0.0
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*/
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export const Equivalence: Equ.Equivalence<number> = Equ.Number
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/**
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* Returns `true` if the first argument is less than the second, otherwise `false`.
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*
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* **When to use**
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*
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* Use to test whether one number is strictly less than another.
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*
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* **Example** (Checking less-than comparisons)
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*
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* ```ts
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* import { Number } from "effect"
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* import * as assert from "node:assert"
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*
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* assert.deepStrictEqual(Number.isLessThan(2, 3), true)
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* assert.deepStrictEqual(Number.isLessThan(3, 3), false)
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* assert.deepStrictEqual(Number.isLessThan(4, 3), false)
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* ```
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*
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* @category predicates
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* @since 4.0.0
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*/
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export const isLessThan: {
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(that: number): (self: number) => boolean
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(self: number, that: number): boolean
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} = order.isLessThan(Order)
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/**
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* Returns a function that checks if a given `number` is less than or equal to the provided one.
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*
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* **When to use**
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*
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* Use to test whether one number is less than or equal to another.
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*
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* **Example** (Checking less-than-or-equal comparisons)
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*
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* ```ts
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* import { Number } from "effect"
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* import * as assert from "node:assert"
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*
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* assert.deepStrictEqual(Number.isLessThanOrEqualTo(2, 3), true)
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* assert.deepStrictEqual(Number.isLessThanOrEqualTo(3, 3), true)
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* assert.deepStrictEqual(Number.isLessThanOrEqualTo(4, 3), false)
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* ```
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*
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* @category predicates
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* @since 4.0.0
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*/
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export const isLessThanOrEqualTo: {
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(that: number): (self: number) => boolean
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(self: number, that: number): boolean
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} = order.isLessThanOrEqualTo(Order)
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/**
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* Returns `true` if the first argument is greater than the second, otherwise `false`.
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*
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* **When to use**
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*
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* Use to test whether one number is strictly greater than another.
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*
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* **Example** (Checking greater-than comparisons)
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*
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* ```ts
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* import { Number } from "effect"
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* import * as assert from "node:assert"
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*
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* assert.deepStrictEqual(Number.isGreaterThan(2, 3), false)
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* assert.deepStrictEqual(Number.isGreaterThan(3, 3), false)
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* assert.deepStrictEqual(Number.isGreaterThan(4, 3), true)
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* ```
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*
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* @category predicates
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* @since 4.0.0
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*/
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export const isGreaterThan: {
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(that: number): (self: number) => boolean
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(self: number, that: number): boolean
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} = order.isGreaterThan(Order)
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/**
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* Returns a function that checks if a given `number` is greater than or equal to the provided one.
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*
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* **When to use**
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*
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* Use to test whether one number is greater than or equal to another.
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*
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* **Example** (Checking greater-than-or-equal comparisons)
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*
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* ```ts
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* import { Number } from "effect"
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* import * as assert from "node:assert"
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*
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* assert.deepStrictEqual(Number.isGreaterThanOrEqualTo(2, 3), false)
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* assert.deepStrictEqual(Number.isGreaterThanOrEqualTo(3, 3), true)
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* assert.deepStrictEqual(Number.isGreaterThanOrEqualTo(4, 3), true)
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* ```
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*
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* @category predicates
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* @since 4.0.0
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*/
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export const isGreaterThanOrEqualTo: {
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(that: number): (self: number) => boolean
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(self: number, that: number): boolean
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} = order.isGreaterThanOrEqualTo(Order)
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/**
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* Checks whether a `number` is between a `minimum` and `maximum` value (inclusive).
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*
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* **When to use**
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*
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* Use to test whether a number falls inside an inclusive range.
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*
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* **Example** (Checking inclusive ranges)
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*
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* ```ts
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* import { Number } from "effect"
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* import * as assert from "node:assert"
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*
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* const between = Number.between({ minimum: 0, maximum: 5 })
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*
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* assert.deepStrictEqual(between(3), true)
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* assert.deepStrictEqual(between(-1), false)
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* assert.deepStrictEqual(between(6), false)
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* ```
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*
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* @see {@link clamp} for forcing a number into an inclusive range
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*
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* @category predicates
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* @since 2.0.0
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*/
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export const between: {
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(options: {
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minimum: number
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maximum: number
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}): (self: number) => boolean
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(self: number, options: {
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minimum: number
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maximum: number
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}): boolean
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} = order.isBetween(Order)
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/**
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* Restricts the given `number` to be within the range specified by the `minimum` and `maximum` values.
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*
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* **When to use**
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*
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* Use to force a number into an inclusive range.
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*
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* **Details**
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*
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* - If the `number` is less than the `minimum` value, the function returns the `minimum` value.
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* - If the `number` is greater than the `maximum` value, the function returns the `maximum` value.
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* - Otherwise, it returns the original `number`.
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*
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* **Example** (Clamping to a range)
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*
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* ```ts
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* import { Number } from "effect"
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* import * as assert from "node:assert"
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*
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* const clamp = Number.clamp({ minimum: 1, maximum: 5 })
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*
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* assert.equal(clamp(3), 3)
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* assert.equal(clamp(0), 1)
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* assert.equal(clamp(6), 5)
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* ```
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*
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* @see {@link between} for checking whether a number is already inside a range
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*
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* @category math
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* @since 2.0.0
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*/
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export const clamp: {
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(options: {
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minimum: number
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maximum: number
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}): (self: number) => number
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(self: number, options: {
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minimum: number
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maximum: number
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}): number
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} = order.clamp(Order)
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/**
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* Returns the minimum between two `number`s.
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*
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* **When to use**
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*
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* Use to select the smaller of two numbers.
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*
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* **Example** (Finding the minimum)
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*
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* ```ts
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* import { Number } from "effect"
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* import * as assert from "node:assert"
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*
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* assert.deepStrictEqual(Number.min(2, 3), 2)
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* ```
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*
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* @see {@link max} for selecting the larger value
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*
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* @category math
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* @since 2.0.0
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*/
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export const min: {
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(that: number): (self: number) => number
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(self: number, that: number): number
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} = order.min(Order)
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/**
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* Returns the maximum between two `number`s.
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*
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* **When to use**
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*
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* Use to select the larger of two numbers.
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*
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* **Example** (Finding the maximum)
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*
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* ```ts
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* import { Number } from "effect"
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* import * as assert from "node:assert"
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*
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* assert.deepStrictEqual(Number.max(2, 3), 3)
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* ```
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*
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* @see {@link min} for selecting the smaller value
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*
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* @category math
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* @since 2.0.0
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*/
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export const max: {
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(that: number): (self: number) => number
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(self: number, that: number): number
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} = order.max(Order)
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/**
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* Determines the sign of a given `number`.
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*
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* **When to use**
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*
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* Use to classify a number as negative, zero, or positive.
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*
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* **Example** (Determining the sign)
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*
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* ```ts
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* import { Number } from "effect"
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* import * as assert from "node:assert"
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*
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* assert.deepStrictEqual(Number.sign(-5), -1)
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* assert.deepStrictEqual(Number.sign(0), 0)
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* assert.deepStrictEqual(Number.sign(5), 1)
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* ```
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*
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* @category math
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* @since 2.0.0
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*/
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export const sign = (n: number): Ordering => Order(n, 0)
|
|
|
|
/**
|
|
* Takes an `Iterable` of `number`s and returns their sum as a single `number`.
|
|
*
|
|
* **When to use**
|
|
*
|
|
* Use to sum all numbers in an iterable.
|
|
*
|
|
* **Example** (Summing an iterable)
|
|
*
|
|
* ```ts
|
|
* import { Number } from "effect"
|
|
* import * as assert from "node:assert"
|
|
*
|
|
* assert.deepStrictEqual(Number.sumAll([2, 3, 4]), 9)
|
|
* ```
|
|
*
|
|
* @see {@link sum} for adding two numbers
|
|
* @see {@link ReducerSum} for summing through APIs that consume a `Reducer`
|
|
*
|
|
* @category math
|
|
* @since 2.0.0
|
|
*/
|
|
export const sumAll = (collection: Iterable<number>): number => {
|
|
let out = 0
|
|
for (const n of collection) {
|
|
out += n
|
|
}
|
|
return out
|
|
}
|
|
|
|
/**
|
|
* Takes an `Iterable` of `number`s and returns their multiplication as a single `number`.
|
|
*
|
|
* **When to use**
|
|
*
|
|
* Use to multiply all numbers in an iterable.
|
|
*
|
|
* **Example** (Multiplying an iterable)
|
|
*
|
|
* ```ts
|
|
* import { Number } from "effect"
|
|
* import * as assert from "node:assert"
|
|
*
|
|
* assert.deepStrictEqual(Number.multiplyAll([2, 3, 4]), 24)
|
|
* ```
|
|
*
|
|
* @see {@link multiply} for multiplying two numbers
|
|
* @see {@link ReducerMultiply} for multiplying through APIs that consume a `Reducer`
|
|
*
|
|
* @category math
|
|
* @since 2.0.0
|
|
*/
|
|
export const multiplyAll = (collection: Iterable<number>): number => {
|
|
let out = 1
|
|
for (const n of collection) {
|
|
if (n === 0) {
|
|
return 0
|
|
}
|
|
out *= n
|
|
}
|
|
return out
|
|
}
|
|
|
|
/**
|
|
* Returns the remainder left over when one operand is divided by a second operand, always taking the sign of the dividend.
|
|
*
|
|
* **When to use**
|
|
*
|
|
* Use to compute a numeric remainder while preserving decimal precision better
|
|
* than direct JavaScript `%` for decimal operands.
|
|
*
|
|
* **Example** (Calculating remainders)
|
|
*
|
|
* ```ts
|
|
* import { Number } from "effect"
|
|
* import * as assert from "node:assert"
|
|
*
|
|
* assert.deepStrictEqual(Number.remainder(2, 2), 0)
|
|
* assert.deepStrictEqual(Number.remainder(3, 2), 1)
|
|
* assert.deepStrictEqual(Number.remainder(-4, 2), -0)
|
|
* ```
|
|
*
|
|
* @see {@link divide} for quotient calculation with division-by-zero represented as `Option.none`
|
|
*
|
|
* @category math
|
|
* @since 2.0.0
|
|
*/
|
|
export const remainder: {
|
|
(divisor: number): (self: number) => number
|
|
(self: number, divisor: number): number
|
|
} = dual(2, (self: number, divisor: number): number => {
|
|
const selfString = self.toString()
|
|
const divisorString = divisor.toString()
|
|
if (selfString.includes("e") || divisorString.includes("e")) {
|
|
if (!globalThis.Number.isFinite(self) || !globalThis.Number.isFinite(divisor) || divisor === 0) {
|
|
return NaN
|
|
}
|
|
return remainderWithScientificNotation(self, divisor)
|
|
}
|
|
const selfDecCount = (selfString.split(".")[1] || "").length
|
|
const divisorDecCount = (divisorString.split(".")[1] || "").length
|
|
const decCount = selfDecCount > divisorDecCount ? selfDecCount : divisorDecCount
|
|
const selfInt = parseInt(self.toFixed(decCount).replace(".", ""))
|
|
const divisorInt = parseInt(divisor.toFixed(decCount).replace(".", ""))
|
|
return (selfInt % divisorInt) / Math.pow(10, decCount)
|
|
})
|
|
|
|
function remainderWithScientificNotation(self: number, divisor: number): number {
|
|
const [selfCoefficient, selfExponent] = toScientificInteger(self)
|
|
const [divisorCoefficient, divisorExponent] = toScientificInteger(divisor)
|
|
const exponent = Math.min(selfExponent, divisorExponent)
|
|
const selfInteger = selfCoefficient * BigInt(10) ** BigInt(selfExponent - exponent)
|
|
const divisorInteger = divisorCoefficient * BigInt(10) ** BigInt(divisorExponent - exponent)
|
|
const out = selfInteger % divisorInteger
|
|
if (out === BigInt(0)) {
|
|
return self < 0 || Object.is(self, -0) ? -0 : 0
|
|
}
|
|
const remainder = globalThis.Number(`${out}e${exponent}`)
|
|
return remainder === 0 ? Math.sign(self) * globalThis.Number.MIN_VALUE : remainder
|
|
}
|
|
|
|
function toScientificInteger(n: number): readonly [coefficient: bigint, exponent: number] {
|
|
const scientific = Math.abs(n).toExponential()
|
|
const eIndex = scientific.indexOf("e")
|
|
const digits = scientific.slice(0, eIndex).replace(".", "")
|
|
const coefficient = BigInt(digits) * (n < 0 ? -BigInt(1) : BigInt(1))
|
|
return [coefficient, globalThis.Number(scientific.slice(eIndex + 1)) - digits.length + 1]
|
|
}
|
|
|
|
/**
|
|
* Returns the next power of 2 from the given number.
|
|
*
|
|
* **When to use**
|
|
*
|
|
* Use to round a number up to the next power of two.
|
|
*
|
|
* **Example** (Finding the next power of two)
|
|
*
|
|
* ```ts
|
|
* import { Number } from "effect"
|
|
* import * as assert from "node:assert"
|
|
*
|
|
* assert.deepStrictEqual(Number.nextPow2(5), 8)
|
|
* assert.deepStrictEqual(Number.nextPow2(17), 32)
|
|
* ```
|
|
*
|
|
* @category math
|
|
* @since 2.0.0
|
|
*/
|
|
export const nextPow2 = (n: number): number => {
|
|
const nextPow = Math.ceil(Math.log(n) / Math.log(2))
|
|
return Math.max(Math.pow(2, nextPow), 2)
|
|
}
|
|
|
|
/**
|
|
* Parses a `number` from a `string` safely using the `Number()` function.
|
|
* The following special string values are supported: "NaN", "Infinity", "-Infinity".
|
|
*
|
|
* **When to use**
|
|
*
|
|
* Use to parse numeric text without throwing on invalid input.
|
|
*
|
|
* **Example** (Parsing numbers from strings)
|
|
*
|
|
* ```ts
|
|
* import { Number } from "effect"
|
|
*
|
|
* Number.parse("42") // Option.some(42)
|
|
* Number.parse("3.14") // Option.some(3.14)
|
|
* Number.parse("NaN") // Option.some(NaN)
|
|
* Number.parse("Infinity") // Option.some(Infinity)
|
|
* Number.parse("-Infinity") // Option.some(-Infinity)
|
|
* Number.parse("not a number") // Option.none()
|
|
* ```
|
|
*
|
|
* @see {@link Number} for native constructor coercion
|
|
*
|
|
* @category constructors
|
|
* @since 2.0.0
|
|
*/
|
|
export const parse = (s: string): Option.Option<number> => {
|
|
if (s === "NaN") {
|
|
return Option.some(NaN)
|
|
}
|
|
if (s === "Infinity") {
|
|
return Option.some(Infinity)
|
|
}
|
|
if (s === "-Infinity") {
|
|
return Option.some(-Infinity)
|
|
}
|
|
if (s.trim() === "") {
|
|
return Option.none()
|
|
}
|
|
const n = Number(s)
|
|
return Number.isNaN(n) ? Option.none() : Option.some(n)
|
|
}
|
|
|
|
/**
|
|
* Returns the number rounded with the given precision.
|
|
*
|
|
* **When to use**
|
|
*
|
|
* Use to round a number to a fixed number of decimal places.
|
|
*
|
|
* **Example** (Rounding with precision)
|
|
*
|
|
* ```ts
|
|
* import { Number } from "effect"
|
|
* import * as assert from "node:assert"
|
|
*
|
|
* assert.deepStrictEqual(Number.round(1.1234, 2), 1.12)
|
|
* assert.deepStrictEqual(Number.round(1.567, 2), 1.57)
|
|
* ```
|
|
*
|
|
* @category math
|
|
* @since 3.8.0
|
|
*/
|
|
export const round: {
|
|
(precision: number): (self: number) => number
|
|
(self: number, precision: number): number
|
|
} = dual(2, (self: number, precision: number): number => {
|
|
const factor = Math.pow(10, precision)
|
|
return Math.round(self * factor) / factor
|
|
})
|
|
|
|
/**
|
|
* Reducer for combining `number`s using addition.
|
|
*
|
|
* **When to use**
|
|
*
|
|
* Use to sum many numbers through APIs that consume a `Reducer`.
|
|
*
|
|
* **Details**
|
|
*
|
|
* The reducer starts from `0`, so `combineAll([])` returns `0`.
|
|
*
|
|
* @see {@link sumAll} for summing an iterable directly
|
|
* @see {@link ReducerMultiply} for multiplying number values
|
|
*
|
|
* @category math
|
|
* @since 4.0.0
|
|
*/
|
|
export const ReducerSum: Reducer.Reducer<number> = Reducer.make((a, b) => a + b, 0)
|
|
|
|
/**
|
|
* Reducer for combining `number`s using multiplication.
|
|
*
|
|
* **When to use**
|
|
*
|
|
* Use to multiply many numbers through APIs that consume a `Reducer`.
|
|
*
|
|
* **Details**
|
|
*
|
|
* The reducer starts from `1`, so reducing an empty collection returns `1`.
|
|
*
|
|
* **Gotchas**
|
|
*
|
|
* Reducing an iterable short-circuits when it sees `0`, so later elements are
|
|
* not consumed.
|
|
*
|
|
* @see {@link multiplyAll} for multiplying an iterable directly
|
|
*
|
|
* @category math
|
|
* @since 4.0.0
|
|
*/
|
|
export const ReducerMultiply: Reducer.Reducer<number> = Reducer.make((a, b) => a * b, 1, (collection) => {
|
|
let acc = 1
|
|
for (const n of collection) {
|
|
if (n === 0) return 0
|
|
acc *= n
|
|
}
|
|
return acc
|
|
})
|
|
|
|
/**
|
|
* Reducer for reducing `number`s by keeping the maximum value.
|
|
*
|
|
* **When to use**
|
|
*
|
|
* Use to keep the largest number through APIs that consume a `Reducer`.
|
|
*
|
|
* **Details**
|
|
*
|
|
* The reducer starts from `-Infinity`, so reducing an empty collection returns
|
|
* `-Infinity`.
|
|
*
|
|
* **Gotchas**
|
|
*
|
|
* `NaN` values propagate through `Math.max`.
|
|
*
|
|
* @see {@link ReducerMin} for keeping the smallest number
|
|
* @see {@link max} for comparing two numbers directly
|
|
*
|
|
* @category math
|
|
* @since 4.0.0
|
|
*/
|
|
export const ReducerMax: Reducer.Reducer<number> = Reducer.make((a, b) => Math.max(a, b), -Infinity)
|
|
|
|
/**
|
|
* Reducer for reducing `number`s by keeping the minimum value.
|
|
*
|
|
* **When to use**
|
|
*
|
|
* Use to keep the smallest number through APIs that consume a `Reducer`.
|
|
*
|
|
* **Details**
|
|
*
|
|
* The reducer starts from `Infinity`, so reducing an empty collection returns
|
|
* `Infinity`.
|
|
*
|
|
* **Gotchas**
|
|
*
|
|
* `NaN` values propagate through `Math.min`.
|
|
*
|
|
* @see {@link ReducerMax} for keeping the largest number
|
|
* @see {@link min} for comparing two numbers directly
|
|
*
|
|
* @category math
|
|
* @since 4.0.0
|
|
*/
|
|
export const ReducerMin: Reducer.Reducer<number> = Reducer.make((a, b) => Math.min(a, b), Infinity)
|