until()

The main function to create an Until instance for watching value changes.

Signature

function until<T>(source: WatchSource<T>): UntilValue<T>

Parameters

source

• Type: WatchSource<T>
• Required: Yes

A WatchSource can be one of:

Type	Example	Description
Getter Function	() => value	A function that returns the current value
Subscribable	{ value, subscribe }	An object with value property and subscribe method
RefLike	{ value }	An object with value property (e.g., Vue ref)
Plain Value	5, 'hello'	A static value (will never change)

Returns

Returns an UntilValue<T> instance with methods for waiting on conditions.

Examples

With Getter Function

import until from 'untiljs'

let count = 0
setTimeout(() => { count = 5 }, 1000)

const result = await until(() => count).toBe(5)
console.log(result) // 5

With Vue Ref

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

const count = ref(0)
setTimeout(() => { count.value = 5 }, 1000)

// Pass ref directly
const result = await until(count).toBe(5)

// Or use getter function
const result2 = await until(() => count.value).toBe(5)

With Subscribable

import until, { createStore } from 'untiljs'

const store = createStore(0)
setTimeout(() => { store.value = 5 }, 1000)

const result = await until(store).toBe(5)

With Plain Value

import until from 'untiljs'

// Plain values never change, so this will timeout
const result = await until(5).toBe(10, { timeout: 1000 })

TypeScript

import until from 'untiljs'

// Type is inferred from source
const result1 = await until(() => 'hello').toBe('hello') // string

// With explicit type
const result2 = await until<number>(() => someNumber).toBe(5)

See Also

• WatchSource
• createStore()
• UntilToMatchOptions