isEmpty

493 bytes

Usage

Pass in a value and get a boolean telling you if the value is empty.

import * as _ from 'radashi'

_.isEmpty([]) // => true
_.isEmpty('') // => true

_.isEmpty('hello') // => false
_.isEmpty(['hello']) // => false

Empty values include:

• null
• undefined
• 0
• empty string
• empty array
• invalid Date time
• object with length property of 0
• object with size property of 0
• object with no enumerable keys

Type Guards

In some cases, isEmpty acts as a type guard, which helps TypeScript infer more specific types based on the check.

Due to TypeScript limitations, object types cannot be narrowed, except for arrays and functions.

import * as _ from 'radashi'

// Example with string
const value1: string = ''
if (_.isEmpty(value1)) {
  // TypeScript infers value1 as ''
  console.log('Value is an empty string')
} else {
  // TypeScript infers value1 as string
  console.log('Value is a non-empty string')
}

// Example with array
const value2: string[] = []
if (_.isEmpty(value2)) {
  // TypeScript infers value2 as never[]
  console.log('Value is an empty array')
} else {
  // TypeScript infers value2 as string[]
  console.log('Value is a non-empty array')
}