toBeNaN()

Wait until the value is NaN.

Signature

toBeNaN(options?: UntilToMatchOptions): Promise<T>

Parameters

options

• Type: UntilToMatchOptions
• Required: No

Options for timeout behavior.

Returns

A Promise that resolves to NaN when the value is NaN.

Examples

Basic Usage

import until from 'untiljs'

let number = 0
setTimeout(() => { number = NaN }, 500)

const result = await until(() => number).toBeNaN()
console.log(result) // NaN

Waiting for Invalid Calculation

import until from 'untiljs'

let result = 0

function divide(a: number, b: number) {
  result = a / b
}

setTimeout(() => divide(1, 0), 1000) // Actually returns Infinity, not NaN
setTimeout(() => divide(NaN, 1), 1500) // This returns NaN

await until(() => result).toBeNaN()
console.log('Got NaN!')

With Timeout

import until from 'untiljs'

let number = 0

const result = await until(() => number).toBeNaN({ timeout: 5000 })

With Vue

import { ref } from 'vue'
import until from 'untiljs'

const value = ref(0)

async function test() {
  value.value = NaN
  await until(value).toBeNaN()
  console.log('Value is NaN')
}

See Also

• not.toBeNaN()
• toMatch()