CODEWITHSUNDEEP
javascriptreactjsreduximmutabilityimmutable.js
Michal
Michal

Reputation: 5220

Working with complicated immutable objects

I have multidimensional array that I would like to have immutable. However I am still not quite sure how am I supposed to work with multidimensional immutable objects.

Lets say that I have structure similar to this one:

// data
{
    // item
    {
        name: someName,
        todos: [
            { id: 1, name: todoName },
            { id: 2, name: todoName2 }
        ]
    }
}

How can I extract unique list of todos?

// Saving todos
let uniqueTodos = []
// Saving ids of todos
let saved = []

// I want to make data immutable list
data.forEach(item => {
  item.todos.forEach(todo => {
    if (saved.indexOf(todo.id) === -1) {
      saved.push(todo.id)
      todos.push(todo)
    }
  })

})
return todos

Upvotes: 0

Views: 98

Answers (1)

Nick Ribal
Nick Ribal

Reputation: 2109

I believe you are confusing two related concepts: immutability - a technique which can be used in JS vs Immutable.js - a library to make the former easy.

Here's an example of both (dataset is corrected a bit to valid JS and to include a duplicate todo):

const data = {
  item: {
    name: 'someName',
    todos: [
      { id: 1, name: 'todoName' },
      { id: 2, name: 'todoName2' },
      { id: 2, name: 'todoName2' },
    ],
  },
}


console.info(
  'immutable unique todos:',
  data.item.todos.map((todo) => ({ ...todo, }))
)

console.info(
  'Immutable.js unique todos:',
  Immutable.fromJS(data).getIn(['item', 'todos']).toSet().toJS()
)
<script src="https://cdn.jsdelivr.net/immutable.js/3.8.1/immutable.min.js"></script>

Immutable.js docs.

Upvotes: 4

Related Questions