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Stack Store

The Stack Store is a data structure for storing items in a last-in, first-out (LIFO) manner. It offers methods to add or remove items, observe changes, and check the current stack size.

Importing and Initializing

To integrate the Stack Store into your project:

import { createStackStore } from '@yobta/stores'

Creating a Store

Initialize the Stack Store with an initial state:

const initialState: string[] = []
const myStack = createStackStore<string>(initialState)

Adding Items

Use the push method to add items. This method returns the new stack size:

myStack.push('item1')

Removing Items

Use the pop method to remove the last item. It returns the removed item or undefined if the stack was empty:

const item = myStack.pop()

Getting the Last Item

Retrieve the last item using the last method:

const lastItem = myStack.last()

Observing Changes

To watch for changes, utilize the observe method:

const observer = (item: string | undefined) => {
  console.log(`New last item: ${item}`)
}
myStack.observe(observer)

Observers are notified with the new last item and any overloads provided to the push or pop methods. This enables more nuanced control and response mechanisms based on stack changes.

Size of the Store

You can check the current size of the stack at any time by calling the size method:

const currentSize = myStack.size()

Overloads

Both push and pop methods accept additional arguments (overloads) that are passed along to observers. This allows for more detailed tracking and reaction to changes in the stack:

myStack.push('newItem', 'additionalInfo')
myStack.pop('contextInfo')

Observers will receive these overloads alongside the stack's latest state, providing rich context for each update.

Example Usage

Here's how you might set up a stack store, add items, remove items, and subscribe to updates:

// Setting up the store
const myStack = createStackStore<string>(['initialItem'])

// Adding an item
myStack.push('anotherItem')

// Observing changes
myStack.observe((item, ...overloads) => {
  console.log(`The last item is now: ${item}`, `Overloads:`, overloads)
})

// Removing the last item
const removedItem = myStack.pop()
console.log(`Removed item: ${removedItem}`)

// Checking the size of the stack
console.log(`Current stack size: ${myStack.size()}`)