veffect
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powerful TypeScript validation library built on the robust foundation of Effect combining exceptional type safety, high performance, and developer experience. Taking inspiration from Effect's functional principles, VEffect delivers a balanced approach tha
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JavaScript
import * as Equal from "./Equal.js";
import * as Equivalence from "./Equivalence.js";
import { constNull, constUndefined, dual, identity, isFunction } from "./Function.js";
import * as either from "./internal/either.js";
import * as option from "./internal/option.js";
import * as order from "./Order.js";
import * as Gen from "./Utils.js";
/**
* @category symbols
* @since 2.0.0
*/
export const TypeId = /*#__PURE__*/Symbol.for("effect/Option");
/**
* Creates a new `Option` that represents the absence of a value.
*
* @category constructors
* @since 2.0.0
*/
export const none = () => option.none;
/**
* Creates a new `Option` that wraps the given value.
*
* @param value - The value to wrap.
*
* @category constructors
* @since 2.0.0
*/
export const some = option.some;
/**
* Tests if a value is a `Option`.
*
* @param input - The value to check.
*
* @example
* import { some, none, isOption } from 'effect/Option'
*
* assert.deepStrictEqual(isOption(some(1)), true)
* assert.deepStrictEqual(isOption(none()), true)
* assert.deepStrictEqual(isOption({}), false)
*
* @category guards
* @since 2.0.0
*/
export const isOption = option.isOption;
/**
* Determine if a `Option` is a `None`.
*
* @param self - The `Option` to check.
*
* @example
* import { some, none, isNone } from 'effect/Option'
*
* assert.deepStrictEqual(isNone(some(1)), false)
* assert.deepStrictEqual(isNone(none()), true)
*
* @category guards
* @since 2.0.0
*/
export const isNone = option.isNone;
/**
* Determine if a `Option` is a `Some`.
*
* @param self - The `Option` to check.
*
* @example
* import { some, none, isSome } from 'effect/Option'
*
* assert.deepStrictEqual(isSome(some(1)), true)
* assert.deepStrictEqual(isSome(none()), false)
*
* @category guards
* @since 2.0.0
*/
export const isSome = option.isSome;
/**
* Matches the given `Option` and returns either the provided `onNone` value or the result of the provided `onSome`
* function when passed the `Option`'s value.
*
* @param self - The `Option` to match
* @param onNone - The value to be returned if the `Option` is `None`
* @param onSome - The function to be called if the `Option` is `Some`, it will be passed the `Option`'s value and its result will be returned
*
* @example
* import { some, none, match } from 'effect/Option'
* import { pipe } from "effect/Function"
*
* assert.deepStrictEqual(
* pipe(some(1), match({ onNone: () => 'a none', onSome: (a) => `a some containing ${a}` })),
* 'a some containing 1'
* )
*
* assert.deepStrictEqual(
* pipe(none(), match({ onNone: () => 'a none', onSome: (a) => `a some containing ${a}` })),
* 'a none'
* )
*
* @category pattern matching
* @since 2.0.0
*/
export const match = /*#__PURE__*/dual(2, (self, {
onNone,
onSome
}) => isNone(self) ? onNone() : onSome(self.value));
/**
* Returns a type guard from a `Option` returning function.
* This function ensures that a type guard definition is type-safe.
*
* @example
* import * as O from "effect/Option"
*
* const parsePositive = (n: number): O.Option<number> =>
* n > 0 ? O.some(n) : O.none()
*
* const isPositive = O.toRefinement(parsePositive)
*
* assert.deepStrictEqual(isPositive(1), true)
* assert.deepStrictEqual(isPositive(-1), false)
*
* @category conversions
* @since 2.0.0
*/
export const toRefinement = f => a => isSome(f(a));
/**
* Converts an `Iterable` of values into an `Option`. Returns the first value of the `Iterable` wrapped in a `Some`
* if the `Iterable` is not empty, otherwise returns `None`.
*
* @param collection - The `Iterable` to be converted to an `Option`.
*
* @example
* import { fromIterable, some, none } from 'effect/Option'
*
* assert.deepStrictEqual(fromIterable([1, 2, 3]), some(1))
* assert.deepStrictEqual(fromIterable([]), none())
*
* @category constructors
* @since 2.0.0
*/
export const fromIterable = collection => {
for (const a of collection) {
return some(a);
}
return none();
};
/**
* Converts a `Either` to an `Option` discarding the error.
*
* Alias of {@link fromEither}.
*
* @example
* import * as O from "effect/Option"
* import * as E from "effect/Either"
*
* assert.deepStrictEqual(O.getRight(E.right('ok')), O.some('ok'))
* assert.deepStrictEqual(O.getRight(E.left('err')), O.none())
*
* @category conversions
* @since 2.0.0
*/
export const getRight = either.getRight;
/**
* Converts a `Either` to an `Option` discarding the value.
*
* @example
* import * as O from "effect/Option"
* import * as E from "effect/Either"
*
* assert.deepStrictEqual(O.getLeft(E.right("ok")), O.none())
* assert.deepStrictEqual(O.getLeft(E.left("a")), O.some("a"))
*
* @category conversions
* @since 2.0.0
*/
export const getLeft = either.getLeft;
/**
* Returns the value of the `Option` if it is `Some`, otherwise returns `onNone`
*
* @param self - The `Option` to get the value of.
* @param onNone - Function that returns the default value to return if the `Option` is `None`.
*
* @example
* import { some, none, getOrElse } from 'effect/Option'
* import { pipe } from "effect/Function"
*
* assert.deepStrictEqual(pipe(some(1), getOrElse(() => 0)), 1)
* assert.deepStrictEqual(pipe(none(), getOrElse(() => 0)), 0)
*
* @category getters
* @since 2.0.0
*/
export const getOrElse = /*#__PURE__*/dual(2, (self, onNone) => isNone(self) ? onNone() : self.value);
/**
* Returns the provided `Option` `that` if `self` is `None`, otherwise returns `self`.
*
* @param self - The first `Option` to be checked.
* @param that - The `Option` to return if `self` is `None`.
*
* @example
* import * as O from "effect/Option"
* import { pipe } from "effect/Function"
*
* assert.deepStrictEqual(
* pipe(
* O.none(),
* O.orElse(() => O.none())
* ),
* O.none()
* )
* assert.deepStrictEqual(
* pipe(
* O.some('a'),
* O.orElse(() => O.none())
* ),
* O.some('a')
* )
* assert.deepStrictEqual(
* pipe(
* O.none(),
* O.orElse(() => O.some('b'))
* ),
* O.some('b')
* )
* assert.deepStrictEqual(
* pipe(
* O.some('a'),
* O.orElse(() => O.some('b'))
* ),
* O.some('a')
* )
*
* @category error handling
* @since 2.0.0
*/
export const orElse = /*#__PURE__*/dual(2, (self, that) => isNone(self) ? that() : self);
/**
* Returns the provided default value as `Some` if `self` is `None`, otherwise returns `self`.
*
* @param self - The first `Option` to be checked.
* @param onNone - Function that returns the default value to return if the `Option` is `None`.
*
* @example
* import * as O from "effect/Option"
* import { pipe } from "effect/Function"
*
* assert.deepStrictEqual(
* pipe(
* O.none(),
* O.orElseSome(() => 'b')
* ),
* O.some('b')
* )
* assert.deepStrictEqual(
* pipe(
* O.some('a'),
* O.orElseSome(() => 'b')
* ),
* O.some('a')
* )
*
* @category error handling
* @since 2.0.0
*/
export const orElseSome = /*#__PURE__*/dual(2, (self, onNone) => isNone(self) ? some(onNone()) : self);
/**
* Similar to `orElse`, but instead of returning a simple union, it returns an `Either` object,
* which contains information about which of the two `Option`s has been chosen.
*
* This is useful when it's important to know whether the value was retrieved from the first `Option` or the second option.
*
* @param self - The first `Option` to be checked.
* @param that - The second `Option` to be considered if the first `Option` is `None`.
*
* @category error handling
* @since 2.0.0
*/
export const orElseEither = /*#__PURE__*/dual(2, (self, that) => isNone(self) ? map(that(), either.right) : map(self, either.left));
/**
* Given an `Iterable` collection of `Option`s, returns the first `Some` found in the collection.
*
* @param collection - An iterable collection of `Option` to be searched.
*
* @example
* import * as O from "effect/Option"
*
* assert.deepStrictEqual(O.firstSomeOf([O.none(), O.some(1), O.some(2)]), O.some(1))
*
* @category error handling
* @since 2.0.0
*/
export const firstSomeOf = collection => {
let out = none();
for (out of collection) {
if (isSome(out)) {
return out;
}
}
return out;
};
/**
* Constructs a new `Option` from a nullable type. If the value is `null` or `undefined`, returns `None`, otherwise
* returns the value wrapped in a `Some`.
*
* @param nullableValue - The nullable value to be converted to an `Option`.
*
* @example
* import * as O from "effect/Option"
*
* assert.deepStrictEqual(O.fromNullable(undefined), O.none())
* assert.deepStrictEqual(O.fromNullable(null), O.none())
* assert.deepStrictEqual(O.fromNullable(1), O.some(1))
*
* @category conversions
* @since 2.0.0
*/
export const fromNullable = nullableValue => nullableValue == null ? none() : some(nullableValue);
/**
* This API is useful for lifting a function that returns `null` or `undefined` into the `Option` context.
*
* @example
* import * as O from "effect/Option"
*
* const parse = (s: string): number | undefined => {
* const n = parseFloat(s)
* return isNaN(n) ? undefined : n
* }
*
* const parseOption = O.liftNullable(parse)
*
* assert.deepStrictEqual(parseOption('1'), O.some(1))
* assert.deepStrictEqual(parseOption('not a number'), O.none())
*
* @category conversions
* @since 2.0.0
*/
export const liftNullable = f => (...a) => fromNullable(f(...a));
/**
* Returns the value of the `Option` if it is a `Some`, otherwise returns `null`.
*
* @param self - The `Option` to extract the value from.
*
* @example
* import * as O from "effect/Option"
*
* assert.deepStrictEqual(O.getOrNull(O.some(1)), 1)
* assert.deepStrictEqual(O.getOrNull(O.none()), null)
*
* @category getters
* @since 2.0.0
*/
export const getOrNull = /*#__PURE__*/getOrElse(constNull);
/**
* Returns the value of the `Option` if it is a `Some`, otherwise returns `undefined`.
*
* @param self - The `Option` to extract the value from.
*
* @example
* import * as O from "effect/Option"
*
* assert.deepStrictEqual(O.getOrUndefined(O.some(1)), 1)
* assert.deepStrictEqual(O.getOrUndefined(O.none()), undefined)
*
* @category getters
* @since 2.0.0
*/
export const getOrUndefined = /*#__PURE__*/getOrElse(constUndefined);
/**
* A utility function that lifts a function that throws exceptions into a function that returns an `Option`.
*
* This function is useful for any function that might throw an exception, allowing the developer to handle
* the exception in a more functional way.
*
* @param f - the function that can throw exceptions.
*
* @example
* import * as O from "effect/Option"
*
* const parse = O.liftThrowable(JSON.parse)
*
* assert.deepStrictEqual(parse("1"), O.some(1))
* assert.deepStrictEqual(parse(""), O.none())
*
* @category conversions
* @since 2.0.0
*/
export const liftThrowable = f => (...a) => {
try {
return some(f(...a));
} catch (e) {
return none();
}
};
/**
* Extracts the value of an `Option` or throws if the `Option` is `None`.
*
* If a default error is sufficient for your use case and you don't need to configure the thrown error, see {@link getOrThrow}.
*
* @param self - The `Option` to extract the value from.
* @param onNone - A function that will be called if the `Option` is `None`. It returns the error to be thrown.
*
* @example
* import * as O from "effect/Option"
*
* assert.deepStrictEqual(
* O.getOrThrowWith(O.some(1), () => new Error('Unexpected None')),
* 1
* )
* assert.throws(() => O.getOrThrowWith(O.none(), () => new Error('Unexpected None')))
*
* @category conversions
* @since 2.0.0
*/
export const getOrThrowWith = /*#__PURE__*/dual(2, (self, onNone) => {
if (isSome(self)) {
return self.value;
}
throw onNone();
});
/**
* Extracts the value of an `Option` or throws if the `Option` is `None`.
*
* The thrown error is a default error. To configure the error thrown, see {@link getOrThrowWith}.
*
* @param self - The `Option` to extract the value from.
* @throws `Error("getOrThrow called on a None")`
*
* @example
* import * as O from "effect/Option"
*
* assert.deepStrictEqual(O.getOrThrow(O.some(1)), 1)
* assert.throws(() => O.getOrThrow(O.none()))
*
* @category conversions
* @since 2.0.0
*/
export const getOrThrow = /*#__PURE__*/getOrThrowWith(() => new Error("getOrThrow called on a None"));
/**
* Maps the `Some` side of an `Option` value to a new `Option` value.
*
* @param self - An `Option` to map
* @param f - The function to map over the value of the `Option`
*
* @category mapping
* @since 2.0.0
*/
export const map = /*#__PURE__*/dual(2, (self, f) => isNone(self) ? none() : some(f(self.value)));
/**
* Maps the `Some` value of this `Option` to the specified constant value.
*
* @category mapping
* @since 2.0.0
*/
export const as = /*#__PURE__*/dual(2, (self, b) => map(self, () => b));
/**
* Maps the `Some` value of this `Option` to the `void` constant value.
*
* This is useful when the value of the `Option` is not needed, but the presence or absence of the value is important.
*
* @category mapping
* @since 2.0.0
*/
export const asUnit = /*#__PURE__*/as(undefined);
/**
* @since 2.0.0
*/
export const unit = /*#__PURE__*/some(undefined);
/**
* Applies a function to the value of an `Option` and flattens the result, if the input is `Some`.
*
* @category sequencing
* @since 2.0.0
*/
export const flatMap = /*#__PURE__*/dual(2, (self, f) => isNone(self) ? none() : f(self.value));
/**
* Executes a sequence of two `Option`s. The second `Option` can be dependent on the result of the first `Option`.
*
* @category sequencing
* @since 2.0.0
*/
export const andThen = /*#__PURE__*/dual(2, (self, f) => flatMap(self, a => {
const b = isFunction(f) ? f(a) : f;
return isOption(b) ? b : some(b);
}));
/**
* This is `flatMap` + `fromNullable`, useful when working with optional values.
*
* @example
* import { some, none, flatMapNullable } from 'effect/Option'
* import { pipe } from "effect/Function"
*
* interface Employee {
* company?: {
* address?: {
* street?: {
* name?: string
* }
* }
* }
* }
*
* const employee1: Employee = { company: { address: { street: { name: 'high street' } } } }
*
* assert.deepStrictEqual(
* pipe(
* some(employee1),
* flatMapNullable(employee => employee.company?.address?.street?.name),
* ),
* some('high street')
* )
*
* const employee2: Employee = { company: { address: { street: {} } } }
*
* assert.deepStrictEqual(
* pipe(
* some(employee2),
* flatMapNullable(employee => employee.company?.address?.street?.name),
* ),
* none()
* )
*
* @category sequencing
* @since 2.0.0
*/
export const flatMapNullable = /*#__PURE__*/dual(2, (self, f) => isNone(self) ? none() : fromNullable(f(self.value)));
/**
* @category sequencing
* @since 2.0.0
*/
export const flatten = /*#__PURE__*/flatMap(identity);
/**
* @category zipping
* @since 2.0.0
*/
export const zipRight = /*#__PURE__*/dual(2, (self, that) => flatMap(self, () => that));
/**
* @category sequencing
* @since 2.0.0
*/
export const composeK = /*#__PURE__*/dual(2, (afb, bfc) => a => flatMap(afb(a), bfc));
/**
* Sequences the specified `that` `Option` but ignores its value.
*
* It is useful when we want to chain multiple operations, but only care about the result of `self`.
*
* @param that - The `Option` that will be ignored in the chain and discarded
* @param self - The `Option` we care about
*
* @category zipping
* @since 2.0.0
*/
export const zipLeft = /*#__PURE__*/dual(2, (self, that) => tap(self, () => that));
/**
* Applies the provided function `f` to the value of the `Option` if it is `Some` and returns the original `Option`
* unless `f` returns `None`, in which case it returns `None`.
*
* This function is useful for performing additional computations on the value of the input `Option` without affecting its value.
*
* @param f - Function to apply to the value of the `Option` if it is `Some`
* @param self - The `Option` to apply the function to
*
* @example
* import * as O from "effect/Option"
*
* const getInteger = (n: number) => Number.isInteger(n) ? O.some(n) : O.none()
*
* assert.deepStrictEqual(O.tap(O.none(), getInteger), O.none())
* assert.deepStrictEqual(O.tap(O.some(1), getInteger), O.some(1))
* assert.deepStrictEqual(O.tap(O.some(1.14), getInteger), O.none())
*
* @category sequencing
* @since 2.0.0
*/
export const tap = /*#__PURE__*/dual(2, (self, f) => flatMap(self, a => map(f(a), () => a)));
/**
* @category combining
* @since 2.0.0
*/
export const product = (self, that) => isSome(self) && isSome(that) ? some([self.value, that.value]) : none();
/**
* @category combining
* @since 2.0.0
*/
export const productMany = (self, collection) => {
if (isNone(self)) {
return none();
}
const out = [self.value];
for (const o of collection) {
if (isNone(o)) {
return none();
}
out.push(o.value);
}
return some(out);
};
/**
* Takes a structure of `Option`s and returns an `Option` of values with the same structure.
*
* - If a tuple is supplied, then the returned `Option` will contain a tuple with the same length.
* - If a struct is supplied, then the returned `Option` will contain a struct with the same keys.
* - If an iterable is supplied, then the returned `Option` will contain an array.
*
* @param fields - the struct of `Option`s to be sequenced.
*
* @example
* import * as O from "effect/Option"
*
* assert.deepStrictEqual(O.all([O.some(1), O.some(2)]), O.some([1, 2]))
* assert.deepStrictEqual(O.all({ a: O.some(1), b: O.some("hello") }), O.some({ a: 1, b: "hello" }))
* assert.deepStrictEqual(O.all({ a: O.some(1), b: O.none() }), O.none())
*
* @category combining
* @since 2.0.0
*/
// @ts-expect-error
export const all = input => {
if (Symbol.iterator in input) {
const out = [];
for (const o of input) {
if (isNone(o)) {
return none();
}
out.push(o.value);
}
return some(out);
}
const out = {};
for (const key of Object.keys(input)) {
const o = input[key];
if (isNone(o)) {
return none();
}
out[key] = o.value;
}
return some(out);
};
/**
* Zips two `Option` values together using a provided function, returning a new `Option` of the result.
*
* @param self - The left-hand side of the zip operation
* @param that - The right-hand side of the zip operation
* @param f - The function used to combine the values of the two `Option`s
*
* @example
* import * as O from "effect/Option"
*
* type Complex = [real: number, imaginary: number]
*
* const complex = (real: number, imaginary: number): Complex => [real, imaginary]
*
* assert.deepStrictEqual(O.zipWith(O.none(), O.none(), complex), O.none())
* assert.deepStrictEqual(O.zipWith(O.some(1), O.none(), complex), O.none())
* assert.deepStrictEqual(O.zipWith(O.none(), O.some(1), complex), O.none())
* assert.deepStrictEqual(O.zipWith(O.some(1), O.some(2), complex), O.some([1, 2]))
*
* assert.deepStrictEqual(O.zipWith(O.some(1), complex)(O.some(2)), O.some([2, 1]))
*
* @category zipping
* @since 2.0.0
*/
export const zipWith = /*#__PURE__*/dual(3, (self, that, f) => map(product(self, that), ([a, b]) => f(a, b)));
/**
* @category combining
* @since 2.0.0
*/
export const ap = /*#__PURE__*/dual(2, (self, that) => zipWith(self, that, (f, a) => f(a)));
/**
* Reduces an `Iterable` of `Option<A>` to a single value of type `B`, elements that are `None` are ignored.
*
* @param self - The Iterable of `Option<A>` to be reduced.
* @param b - The initial value of the accumulator.
* @param f - The reducing function that takes the current accumulator value and the unwrapped value of an `Option<A>`.
*
* @example
* import { some, none, reduceCompact } from 'effect/Option'
* import { pipe } from "effect/Function"
*
* const iterable = [some(1), none(), some(2), none()]
* assert.deepStrictEqual(pipe(iterable, reduceCompact(0, (b, a) => b + a)), 3)
*
* @category folding
* @since 2.0.0
*/
export const reduceCompact = /*#__PURE__*/dual(3, (self, b, f) => {
let out = b;
for (const oa of self) {
if (isSome(oa)) {
out = f(out, oa.value);
}
}
return out;
});
/**
* Transforms an `Option` into an `Array`.
* If the input is `None`, an empty array is returned.
* If the input is `Some`, the value is wrapped in an array.
*
* @param self - The `Option` to convert to an array.
*
* @example
* import * as O from "effect/Option"
*
* assert.deepStrictEqual(O.toArray(O.some(1)), [1])
* assert.deepStrictEqual(O.toArray(O.none()), [])
*
* @category conversions
* @since 2.0.0
*/
export const toArray = self => isNone(self) ? [] : [self.value];
/**
* @category filtering
* @since 2.0.0
*/
export const partitionMap = /*#__PURE__*/dual(2, (self, f) => {
if (isNone(self)) {
return [none(), none()];
}
const e = f(self.value);
return either.isLeft(e) ? [some(e.left), none()] : [none(), some(e.right)];
});
/**
* Maps over the value of an `Option` and filters out `None`s.
*
* Useful when in addition to filtering you also want to change the type of the `Option`.
*
* @param self - The `Option` to map over.
* @param f - A function to apply to the value of the `Option`.
*
* @example
* import * as O from "effect/Option"
*
* const evenNumber = (n: number) => n % 2 === 0 ? O.some(n) : O.none()
*
* assert.deepStrictEqual(O.filterMap(O.none(), evenNumber), O.none())
* assert.deepStrictEqual(O.filterMap(O.some(3), evenNumber), O.none())
* assert.deepStrictEqual(O.filterMap(O.some(2), evenNumber), O.some(2))
*
* @category filtering
* @since 2.0.0
*/
export const filterMap = /*#__PURE__*/dual(2, (self, f) => isNone(self) ? none() : f(self.value));
/**
* Filters an `Option` using a predicate. If the predicate is not satisfied or the `Option` is `None` returns `None`.
*
* If you need to change the type of the `Option` in addition to filtering, see `filterMap`.
*
* @param predicate - A predicate function to apply to the `Option` value.
* @param fb - The `Option` to filter.
*
* @example
* import * as O from "effect/Option"
*
* // predicate
* const isEven = (n: number) => n % 2 === 0
*
* assert.deepStrictEqual(O.filter(O.none(), isEven), O.none())
* assert.deepStrictEqual(O.filter(O.some(3), isEven), O.none())
* assert.deepStrictEqual(O.filter(O.some(2), isEven), O.some(2))
*
* // refinement
* const isNumber = (v: unknown): v is number => typeof v === "number"
*
* assert.deepStrictEqual(O.filter(O.none(), isNumber), O.none())
* assert.deepStrictEqual(O.filter(O.some('hello'), isNumber), O.none())
* assert.deepStrictEqual(O.filter(O.some(2), isNumber), O.some(2))
*
* @category filtering
* @since 2.0.0
*/
export const filter = /*#__PURE__*/dual(2, (self, predicate) => filterMap(self, b => predicate(b) ? option.some(b) : option.none));
/**
* @example
* import { none, some, getEquivalence } from 'effect/Option'
* import * as N from 'effect/Number'
*
* const isEquivalent = getEquivalence(N.Equivalence)
* assert.deepStrictEqual(isEquivalent(none(), none()), true)
* assert.deepStrictEqual(isEquivalent(none(), some(1)), false)
* assert.deepStrictEqual(isEquivalent(some(1), none()), false)
* assert.deepStrictEqual(isEquivalent(some(1), some(2)), false)
* assert.deepStrictEqual(isEquivalent(some(1), some(1)), true)
*
* @category equivalence
* @since 2.0.0
*/
export const getEquivalence = isEquivalent => Equivalence.make((x, y) => x === y || (isNone(x) ? isNone(y) : isNone(y) ? false : isEquivalent(x.value, y.value)));
/**
* The `Order` instance allows `Option` values to be compared with
* `compare`, whenever there is an `Order` instance for
* the type the `Option` contains.
*
* `None` is considered to be less than any `Some` value.
*
* @example
* import { none, some, getOrder } from 'effect/Option'
* import * as N from 'effect/Number'
* import { pipe } from "effect/Function"
*
* const O = getOrder(N.Order)
* assert.deepStrictEqual(O(none(), none()), 0)
* assert.deepStrictEqual(O(none(), some(1)), -1)
* assert.deepStrictEqual(O(some(1), none()), 1)
* assert.deepStrictEqual(O(some(1), some(2)), -1)
* assert.deepStrictEqual(O(some(1), some(1)), 0)
*
* @category sorting
* @since 2.0.0
*/
export const getOrder = O => order.make((self, that) => isSome(self) ? isSome(that) ? O(self.value, that.value) : 1 : -1);
/**
* Lifts a binary function into `Option`.
*
* @param f - The function to lift.
*
* @category lifting
* @since 2.0.0
*/
export const lift2 = f => dual(2, (self, that) => zipWith(self, that, f));
/**
* Transforms a `Predicate` function into a `Some` of the input value if the predicate returns `true` or `None`
* if the predicate returns `false`.
*
* @param predicate - A `Predicate` function that takes in a value of type `A` and returns a boolean.
*
* @example
* import * as O from "effect/Option"
*
* const getOption = O.liftPredicate((n: number) => n >= 0)
*
* assert.deepStrictEqual(getOption(-1), O.none())
* assert.deepStrictEqual(getOption(1), O.some(1))
*
* @category lifting
* @since 2.0.0
*/
export const liftPredicate = predicate => b => predicate(b) ? some(b) : none();
/**
* Returns a function that checks if a `Option` contains a given value using a provided `isEquivalent` function.
*
* @param equivalent - An `Equivalence` instance to compare values of the `Option`.
* @param self - The `Option` to apply the comparison to.
* @param a - The value to compare against the `Option`.
*
* @example
* import { some, none, containsWith } from 'effect/Option'
* import { Equivalence } from 'effect/Number'
* import { pipe } from "effect/Function"
*
* assert.deepStrictEqual(pipe(some(2), containsWith(Equivalence)(2)), true)
* assert.deepStrictEqual(pipe(some(1), containsWith(Equivalence)(2)), false)
* assert.deepStrictEqual(pipe(none(), containsWith(Equivalence)(2)), false)
*
* @category elements
* @since 2.0.0
*/
export const containsWith = isEquivalent => dual(2, (self, a) => isNone(self) ? false : isEquivalent(self.value, a));
const _equivalence = /*#__PURE__*/Equal.equivalence();
/**
* Returns a function that checks if an `Option` contains a given value using the default `Equivalence`.
*
* @category elements
* @since 2.0.0
*/
export const contains = /*#__PURE__*/containsWith(_equivalence);
/**
* Check if a value in an `Option` type meets a certain predicate.
*
* @param self - The `Option` to check.
* @param predicate - The condition to check.
*
* @example
* import { some, none, exists } from 'effect/Option'
* import { pipe } from "effect/Function"
*
* const isEven = (n: number) => n % 2 === 0
*
* assert.deepStrictEqual(pipe(some(2), exists(isEven)), true)
* assert.deepStrictEqual(pipe(some(1), exists(isEven)), false)
* assert.deepStrictEqual(pipe(none(), exists(isEven)), false)
*
* @since 2.0.0
*/
export const exists = /*#__PURE__*/dual(2, (self, refinement) => isNone(self) ? false : refinement(self.value));
// -------------------------------------------------------------------------------------
// do notation
// -------------------------------------------------------------------------------------
/**
* @category do notation
* @since 2.0.0
*/
export const bindTo = /*#__PURE__*/dual(2, (self, name) => map(self, a => ({
[name]: a
})));
const let_ = /*#__PURE__*/dual(3, (self, name, f) => map(self, a => Object.assign({}, a, {
[name]: f(a)
})));
export {
/**
* @category do notation
* @since 2.0.0
*/
let_ as let };
/**
* @category do notation
* @since 2.0.0
*/
export const bind = /*#__PURE__*/dual(3, (self, name, f) => flatMap(self, a => map(f(a), b => Object.assign({}, a, {
[name]: b
}))));
/**
* @category do notation
* @since 2.0.0
*/
export const Do = /*#__PURE__*/some({});
const adapter = /*#__PURE__*/Gen.adapter();
/**
* @category generators
* @since 2.0.0
*/
export const gen = f => {
const iterator = f(adapter);
let state = iterator.next();
if (state.done) {
return some(state.value);
} else {
let current = state.value.value;
if (isNone(current)) {
return current;
}
while (!state.done) {
state = iterator.next(current.value);
if (!state.done) {
current = state.value.value;
if (isNone(current)) {
return current;
}
}
}
return some(state.value);
}
};
//# sourceMappingURL=Option.js.map