<A>(O: Order<A>): {
(that: A): (self: A) => boolean
(self: A, that: A): boolean
}Checks whether one value is strictly greater than another according to the given order.
When to use
Use when you need a boolean greater-than predicate using an Order.
Details
Returns true if the order returns 1, meaning the first value is greater
than the second. Equal or lesser values return false.
Example (Checking greater-than comparisons)
import { Order } from "effect"
const isGreaterThanNumber = Order.isGreaterThan(Order.Number)
console.log(isGreaterThanNumber(2, 1)) // true
console.log(isGreaterThanNumber(1, 2)) // false
console.log(isGreaterThanNumber(1, 1)) // falseexport const const isGreaterThan: <A>(O: Order<A>) => {
(that: A): (self: A) => boolean
(self: A, that: A): boolean
}
Checks whether one value is strictly greater than another according to the given order.
When to use
Use when you need a boolean greater-than predicate using an Order.
Details
Returns true if the order returns 1, meaning the first value is greater
than the second. Equal or lesser values return false.
Example (Checking greater-than comparisons)
import { Order } from "effect"
const isGreaterThanNumber = Order.isGreaterThan(Order.Number)
console.log(isGreaterThanNumber(2, 1)) // true
console.log(isGreaterThanNumber(1, 2)) // false
console.log(isGreaterThanNumber(1, 1)) // false
isGreaterThan = <function (type parameter) A in <A>(O: Order<A>): {
(that: A): (self: A) => boolean;
(self: A, that: A): boolean;
}
type O: Order<A>O: interface Order<in A>Represents a total ordering for values of type A.
When to use
Use when you need to define how values of a type are compared.
Details
An order returns -1 when the first value is less than the second, 0 when
the values are equal according to this ordering, and 1 when the first value
is greater than the second. It must satisfy total ordering laws: totality,
antisymmetry, and transitivity.
Example (Defining a custom Order)
import { Order } from "effect"
const byAge: Order.Order<{ name: string; age: number }> = (self, that) => {
if (self.age < that.age) return -1
if (self.age > that.age) return 1
return 0
}
const person1 = { name: "Alice", age: 30 }
const person2 = { name: "Bob", age: 25 }
console.log(byAge(person1, person2)) // 1
Order<function (type parameter) A in <A>(O: Order<A>): {
(that: A): (self: A) => boolean;
(self: A, that: A): boolean;
}
that: Athat: function (type parameter) A in <A>(O: Order<A>): {
(that: A): (self: A) => boolean;
(self: A, that: A): boolean;
}
self: Aself: function (type parameter) A in <A>(O: Order<A>): {
(that: A): (self: A) => boolean;
(self: A, that: A): boolean;
}
self: Aself: function (type parameter) A in <A>(O: Order<A>): {
(that: A): (self: A) => boolean;
(self: A, that: A): boolean;
}
that: Athat: function (type parameter) A in <A>(O: Order<A>): {
(that: A): (self: A) => boolean;
(self: A, that: A): boolean;
}
dual<(...args: Array<any>) => any, (self: A, that: A) => boolean>(arity: 2, body: (self: A, that: A) => boolean): ((...args: Array<any>) => any) & ((self: A, that: A) => boolean) (+1 overload)Creates a function that can be called in data-first style or data-last
(pipe-friendly) style.
When to use
Use to expose one implementation through both direct and pipe-friendly
call styles.
Details
Pass either the arity of the uncurried function or a predicate that decides
whether the current call is data-first. Arity is the common case. Use a
predicate when optional arguments make arity ambiguous.
Example (Selecting data-first or data-last style by arity)
import { Function, pipe } from "effect"
const sum = Function.dual<
(that: number) => (self: number) => number,
(self: number, that: number) => number
>(2, (self, that) => self + that)
console.log(sum(2, 3)) // 5
console.log(pipe(2, sum(3))) // 5
Example (Defining overloads with call signatures)
import { Function, pipe } from "effect"
const sum: {
(that: number): (self: number) => number
(self: number, that: number): number
} = Function.dual(2, (self: number, that: number): number => self + that)
console.log(sum(2, 3)) // 5
console.log(pipe(2, sum(3))) // 5
Example (Selecting data-first or data-last style with a predicate)
import { Function, pipe } from "effect"
const sum = Function.dual<
(that: number) => (self: number) => number,
(self: number, that: number) => number
>(
(args) => args.length === 2,
(self, that) => self + that
)
console.log(sum(2, 3)) // 5
console.log(pipe(2, sum(3))) // 5
dual(2, (self: Aself: function (type parameter) A in <A>(O: Order<A>): {
(that: A): (self: A) => boolean;
(self: A, that: A): boolean;
}
that: Athat: function (type parameter) A in <A>(O: Order<A>): {
(that: A): (self: A) => boolean;
(self: A, that: A): boolean;
}
type O: Order<A>O(self: Aself, that: Athat) === 1)