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pickFalsy

Returns a falsy check function for selected types.

You may not want numeric 0, empty string (""), empty array ([]), or empty object ({}) to be considered falsy. In that case, you can specify which types to treat as falsy using the type argument.

  • Specifying 'number' treats numeric 0 as falsy.
  • Specifying 'string' treats empty string ("") as falsy.
  • Specifying 'array' treats empty array ([]) as falsy.
  • Specifying 'object' treats empty object ({}) as falsy.

By default, falsy checks are only performed for false, null, undefined, and NaN.


Code​

🔗 View source code


Interface​

typescript
type FalsyCheckKey = "string" | "number" | "object" | "array"

function pickFalsy(...falsyCheckList: FalsyCheckKey[]): <T>(value: T) => boolean

Usage​

Basic Usage​

typescript
import { pickFalsy } from '@modern-kit/utils';

const isInvalidValue = pickFalsy()

isInvalidValue(null) // true
isInvalidValue(undefined) // true
isInvalidValue(false) // true
isInvalidValue(NaN) // true

isInvalidValue('') // false
isInvalidValue(0) // false
isInvalidValue([]) // false
isInvalidValue({}) // false

Adding Specific Types as Falsy​

typescript
import { pickFalsy } from '@modern-kit/utils';

const isInvalidValue = pickFalsy('string')
isInvalidValue('') // true
isInvalidValue('a') // false
typescript
const isInvalidValue = pickFalsy('number')
isInvalidValue(0) // true
isInvalidValue(1) // false
typescript
const isInvalidValue = pickFalsy('array')
isInvalidValue([]) // true
isInvalidValue([1, 2, 3]) // false
typescript
const isInvalidValue = pickFalsy('object')
isInvalidValue({}) // true
isInvalidValue({ a: 1 }) // false

Adding All Types as Falsy​

typescript
import { pickFalsy } from '@modern-kit/utils';

const isInvalidValue = pickFalsy('string', 'number', 'array', 'object')

isInvalidValue(null) // true
isInvalidValue(undefined) // true
isInvalidValue(false) // true
isInvalidValue('') // true
isInvalidValue(0) // true
isInvalidValue([]) // true
isInvalidValue({}) // true