A small utility for managing an undo stack
npm install undo-stackerA small utility for managing an undo stack.
``js
import createStack from 'undo-stacker'
let value = { answer: 42 }
const stack = createStack(value)
// undo/redo have no effect if we're at the
// beginning/end of the stack
console.log((value = stack.undo())) // { answer: 42 }
console.log((value = stack.redo())) // { answer: 42 }
// stack.push returns the new value
value = stack.push({ answer: 43 })
value = stack.push({ answer: 44 })
value = stack.push({ answer: 45 })
console.log(value) // { answer: 45 }
console.log((value = stack.undo())) // { answer: 44 }
console.log((value = stack.undo())) // { answer: 43 }
console.log((value = stack.undo())) // { answer: 42 }
console.log((value = stack.undo())) // { answer: 42 }
console.log((value = stack.redo())) // { answer: 43 }
// pushing clears anything 'forward' in the stack
value = stack.push({ answer: 99 })
// you can also pass a function to push
value = stack.push(value => ({ answer: value.answer + 1 }))
console.log((value = stack.undo())) // { answer: 99 }
console.log((value = stack.undo())) // { answer: 43 }
console.log((value = stack.redo())) // { answer: 99 }
console.log((value = stack.redo())) // { answer: 100 }
console.log((value = stack.redo())) // { answer: 100 }
``
Don't mutate the objects you push to the undo stack; chaos will result. Instead, create a fresh copy each time, either manually or using something like Immer.
This is an exact copy of svelte-undo without the svelte dependency.
MIT