Skip to main content

Function: not()

not<T>(predicate): Predicate<T>

Defined in: predicate/combinators/index.ts:127

Negates a predicate.

Returns a predicate that returns the opposite boolean value.

Type Parameters​

T​

T

Parameters​

predicate​

Predicate<T>

The predicate to negate

Returns​

Predicate<T>

A predicate that returns the opposite of the input predicate

Example​

import * as R from 'remeda'
import { eq, not, isEmpty } from 'receta/predicate'

const numbers = [1, 2, 3, 2, 1]
R.filter(numbers, not(eq(2))) // => [1, 3, 1]

// Real-world: Filter non-empty strings
const names = ['Alice', '', 'Bob', '', 'Charlie']
R.filter(names, not(isEmpty)) // => ['Alice', 'Bob', 'Charlie']

// Complex negation
const users = [
  { name: 'Alice', admin: true },
  { name: 'Bob', admin: false },
  { name: 'Charlie', admin: false }
]
R.filter(users, not((u) => u.admin)) // => non-admin users

See​

  • and - for logical AND
  • or - for logical OR