O | /mod.ts | ahh@v0.10.1

class O

Re-export

import { O } from "https://deno.land/x/ahh@v0.10.1/mod.ts";

Functionality for Option.

Static Methods

and<T, U>(opt: Option<T>, other: Option<U>): Option<U>

Return other if opt is Some, or None.

Examples

import { O, None } from "./mod.ts";

console.log(O.and(1, 2)); // 2
console.log(O.and(None, 2)); // None
console.log(O.and(2, None)); // None
console.log(O.and(None, None)); // None

contains<T>(opt: Option<T>, value: T): boolean

Returns whether opt strictly equals value, or false if it is a None.

Examples

import { O, None } from "./mod.ts";

console.log(O.contains(1, 1)); // true
console.log(O.contains(1, 2)); // false
console.log(O.contains(None, 1)); // false

filter<T>(opt: Option<T>, f: (_: T) => boolean): Option<T>

Calls f with opt, and returns it if the result is true.

Examples

import { O, None } from "./mod.ts";

console.log(O.filter(2, (i) => i % 2 === 0)); // 2
console.log(O.filter(1, (i) => i % 2 === 0)); // None
console.log(O.filter(None, (i: number) => i % 2 === 0)); // None

inspect<T>(opt: Option<T>, f: (_: T) => unknown): Option<T>

Calls f with opt, and returns the original opt.

Examples

import { O, None } from "./mod.ts";

console.log(O.inspect(1, (i) => i + 1)); // 1
console.log(O.inspect(None, (i: number) => i + 1)); // undefined

isNone<T>(opt: Option<T>): opt is None

Returns whether opt is a None.

Examples

import { O, None } from "./mod.ts";

console.log(O.isNone(1)); // false
console.log(O.isNone(None)); // true

isSome<T>(opt: Option<T>): opt is Some<T>

Returns whether opt is a Some.

Examples

import { O, None } from "./mod.ts";

console.log(O.isSome(1)); // true
console.log(O.isSome(None)); // false

map<T, U>(opt: Option<T>, f: (_: T) => U): Option<U>

Calls f with opt, and returns the result.

Examples

import { O, None } from "./mod.ts";

console.log(O.map(1, (i) => i + 1)); // 2
console.log(O.map(None, (i: number) => i + 1)); // undefined

okOr<T, E extends Error>(opt: Option<T>, err: E): Result<T, E>

Converts opt into an Ok if it is a Some.

Examples

import { O, None } from "./mod.ts";

console.log(O.okOr(1, Error())); // 1
console.log(O.okOr(None, Error())); // Error()

or<T>(opt: Option<T>, other: Option<T>): Option<T>

Return opt if it is a Some, or other.

Examples

import { O, None } from "./mod.ts";

console.log(O.or(1, 2)); // 1
console.log(O.or(None, 2)); // 2
console.log(O.or(2, None)); // 2
console.log(O.or(None, None)); // undefined

unwrap<T>(opt: Option<T>): opt extends Some<T> ? T : never

Returns opt if it is a Some, or throws.

Examples

import { O, None } from "./mod.ts";

console.log(O.unwrap(1)); // 1
O.unwrap(None); // throws

unwrapOr<T>(opt: Option<T>, default_: T): T

Returns opt if it is a Some, or returns default_.

Examples

import { O, None } from "./mod.ts";

console.log(O.unwrapOr(1, 2)); // 1
console.log(O.unwrapOr(None, 2)); // 2