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x/jotai/tests/types.test.tsx

👻 Primitive and flexible state management for React
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import { expectType } from 'ts-expect'import { atom, useAtom } from 'jotai'import type { Atom, PrimitiveAtom, WritableAtom } from 'jotai'import type { SetAtom } from '../src/core/atom'
it('atom() should return the correct types', () => { function Component() { // primitive atom const primitiveAtom = atom(0) expectType<PrimitiveAtom<number>>(primitiveAtom)
// read-only derived atom const readonlyDerivedAtom = atom((get) => get(primitiveAtom) * 2) expectType<Atom<number>>(readonlyDerivedAtom)
// read-write derived atom const readWriteDerivedAtom = atom( (get) => get(primitiveAtom), (get, set, value: number) => { set(primitiveAtom, get(primitiveAtom) + value) } ) expectType<WritableAtom<number, number>>(readWriteDerivedAtom)
// write-only derived atom const writeonlyDerivedAtom = atom(null, (get, set) => { set(primitiveAtom, get(primitiveAtom) - 1) }) expectType<WritableAtom<null, number>>(writeonlyDerivedAtom) } Component})
it('useAtom should return the correct types', () => { function Component() { // primitive atom const primitiveAtom = atom(0) expectType<[number, SetAtom<number, void>]>(useAtom(primitiveAtom))
// read-only derived atom const readonlyDerivedAtom = atom((get) => get(primitiveAtom) * 2) expectType<[number, SetAtom<number, void>]>(useAtom(readonlyDerivedAtom))
// read-write derived atom const readWriteDerivedAtom = atom( (get) => get(primitiveAtom), (get, set, value: number) => { set(primitiveAtom, get(primitiveAtom) + value) } ) expectType<[number, SetAtom<number, void>]>(useAtom(readWriteDerivedAtom))
// write-only derived atom const writeonlyDerivedAtom = atom(null, (get, set) => { set(primitiveAtom, get(primitiveAtom) - 1) }) expectType<[null, SetAtom<number, void>]>(useAtom(writeonlyDerivedAtom)) } Component})