isSignal

Type guard function that determines whether a value is a signal (either an Atom or Computed).

This utility function is helpful when working with mixed data types and you need to differentiate between regular values and reactive signal containers. It returns true if the provided value is either an atomic signal created with atom() or a computed signal created with computed().

function isSignal(value: any): value is Signal<any>

Example

import { atom, computed, isSignal } from '@tldraw/state'

const count = atom('count', 5)
const doubled = computed('doubled', () => count.get() * 2)
const regularValue = 'hello'

console.log(isSignal(count)) // true
console.log(isSignal(doubled)) // true
console.log(isSignal(regularValue)) // false
console.log(isSignal(null)) // false

Parameters

any

Returns

value is Signal<any>

true if the value is a Signal (Atom or Computed), false otherwise