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// EFFECT DAYS 2026

utils

19 exports Since v0.21.0 Source

Other

Asserts that actual is equal to expected using the Equal.equals trait.

Signature

declare function assertEquals<A>(actual: A, expected: A, message?: string, ..._: Array<never>): void

Asserts that exit is a failure.

Signature

declare function assertFailure<A, E>(exit: Exit<A, E>, expected: Cause<E>, ..._: Array<never>): asserts exit is Failure<never, E>

Asserts that self is false.

Signature

declare function assertFalse(self: boolean, message?: string, ..._: Array<never>): void

Asserts that actual includes expected.

Signature

declare function assertInclude(actual: string | undefined, expected: string, ..._: Array<never>): void

Asserts that value is an instance of constructor.

Signature

declare function assertInstanceOf<C extends (...args: any) => any>(value: unknown, constructor: C, message?: string, ..._: Array<never>): asserts value is InstanceType<C>

Asserts that either is Left.

Signature

declare function assertLeft<R, L>(either: Either<R, L>, expected: L, ..._: Array<never>): asserts either is Left<L, never>

Asserts that actual matches regexp.

Signature

declare function assertMatch(actual: string, regexp: RegExp, ..._: Array<never>): void

Asserts that option is None.

Signature

declare function assertNone<A>(option: Option<A>, ..._: Array<never>): asserts option is None<never>

Asserts that either is Right.

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declare function assertRight<R, L>(either: Either<R, L>, expected: R, ..._: Array<never>): asserts either is Right<never, R>

Asserts that option is Some.

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declare function assertSome<A>(option: Option<A>, expected: A, ..._: Array<never>): asserts option is Some<A>

Asserts that exit is a success.

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declare function assertSuccess<A, E>(exit: Exit<A, E>, expected: A, ..._: Array<never>): asserts exit is Success<A, never>

Asserts that self is true.

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declare function assertTrue(self: unknown, message?: string, ..._: Array<never>): asserts self

Asserts that actual is equal to expected using the Equal.equals trait.

Signature

declare function deepStrictEqual<A>(actual: A, expected: A, message?: string, ..._: Array<never>): void

Asserts that thunk does not throw an error.

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declare function doesNotThrow(thunk: () => void, message?: string, ..._: Array<never>): void
Since v0.21.0

Throws an AssertionError with the provided error message.

Signature

declare function fail(message: string): void

Asserts that actual is not equal to expected using the Equal.equals trait.

Signature

declare function notDeepStrictEqual<A>(actual: A, expected: A, message?: string, ..._: Array<never>): void

Asserts that actual is equal to expected using the Equal.equals trait.

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declare function strictEqual<A>(actual: A, expected: A, message?: string, ..._: Array<never>): void
Since v0.21.0

Asserts that thunk throws an error.

Signature

declare function throws(thunk: () => void, error?: Error | (u: unknown) => undefined, ..._: Array<never>): void

Asserts that thunk throws an error.

Signature

declare function throwsAsync(thunk: () => Promise<void>, error?: Error | (u: unknown) => undefined, ..._: Array<never>): Promise<void>