immer-producer-2

producer.js

import produce from "immer"

const todos = [ /* 2 todo objects in here */ ]

const nextTodos = produce(todos, draft => {
    draft.push({ text: "learn immer", done: true })
    draft[1].done = true
})

// old state is unmodified
console.log(todos.length)        // 2
console.log(todos[1].done)       // false

// new state reflects the draft
console.log(nextTodos.length)    // 3
console.log(nextTodos[1].done)   // true

// structural sharing
console.log(todos === nextTodos)       // false
console.log(todos[0] === nextTodos[0]) // true
console.log(todos[1] === nextTodos[1]) // false