Nano Stores DeepMap

Deep maps extension for Nano Stores state manager.

Install

npm install @nanostores/deep-map

Usage

Import deepMap from this package instead of nanostores (which no longer has it).

Use setKey to create, replace, or delete any value at a specific path.

import { deepMap } from '@nanostores/deep-map'

type StoreProps = {
  user?: {
    name: string
    age: number
  }
  count?: number
}

const $store = deepMap<StoreProps>({
  user: {
    name: 'Luke',
    age: 19,
  }
  count: 0,
})

// Replaces the value at 'count'
$store.setKey('count', 1) // -> { ...restValues, count: 1 }

Use updateKey to merge new data into an existing object. If the target isn't an object, it will be replaced.

// 'updateKey' merges, keeping 'name' and only changing 'age'
$store.updateKey('user', { age: 42 })
// -> { user: { name: 'Luke', age: 42 }, ... }

To delete a property from an object or an item from an array, just set its path to undefined.

// Deletes 'count' from the store
$store.setKey('count', undefined)
// -> { user: { name: 'Luke', age: 42 } }

Working with Arrays

DeepMap fully supports arrays as the root value or nested within your state. You can use standard array syntax [index] in your paths.

//Before
const $store = deepMap<storeProps[]>([{}]) // Type Error

//After
const $store = deepMap<storeProps[]>([{}]) // OK

TypeScript Support

The package is written in TypeScript and provides autocomplete for all methods and properties.

// Define your type with 'type' keyword instead of 'interface'
// for better autocomplete
type UserType = {
  id?: string
}

const $userT = deepMap<UserType>({})

$userT.setKey('id', 'uuidString') // Suggestion autocomplete

Typescript automatically infers the type of the store value.

type StoreProps = {
  count?: number
}

const $store = deepMap<StoreProps>({})

$store.setKey('count', 'randomString')
// Type Error -> 'string' is not assignable to 'number'

// IMPORTANT: an empty path ('') is treated as the root object
$someStore.setKey('', 'randomString') // Replaces the entire store

License

MIT

Credits

• Nano stores, the original state manager.