Immutable.js Map values to array

问题

I am using the immutable Map from http://facebook.github.io/immutable-js/docs/#/Map

I need to get an array of the values out to pass to a backend service and I think I am missing something basic, how do I do it ?

I have tried :

mymap.valueSeq().toArray()

But I still get an immutable data structure back ?

For example :

var d = '[{"address":"10.0.35.118","cpus":4}]';
var sr = JSON.parse(d);
var is = Immutable.fromJS(sr);

console.log(sr);

console.log(is.toArray());
console.log(is.valueSeq().toArray());

See this http://jsfiddle.net/3sjq148f/2/

The array that we get back from the immutable data structure seems to still be adorned with the immutable fields for each contained object. Is that to be expected ?

回答1:

It's because the sr is an Array of Object, so if you use .fromJS to convert it, it becomes List of Map.

The is.valueSeq().toArray();(valueSeq is not necessary here.) converts it to Array of Map, so you need to loop through the array, and convert each Map item to Array.

var d = '[{"address":"10.0.35.118","cpus":4}]';
var sr = JSON.parse(d);

// Array of Object => List of Map
var is = Immutable.fromJS(sr);

console.log(sr);
console.log(is.toArray());

// Now its Array of Map
var list = is.valueSeq().toArray();

console.log(list);

list.forEach(function(item) {
  
  // Convert Map to Array
  console.log(item.toArray());
});

<script src="https://cdnjs.cloudflare.com/ajax/libs/immutable/3.7.5/immutable.min.js"></script>

回答2:

Just use someMap.toIndexedSeq().toArray() for getting an array of only values.

回答3:

Map.values() returns an ES6 Iterable (as do Map.keys() and Map.entries()), and therefore you can convert to an array with Array.from() or the spread operator (as described in this answer).

e.g.:

Array.from(map.values())

or just

[...map.values()]

来源：https://stackoverflow.com/questions/33148796/immutable-js-map-values-to-array

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javascript

immutable.js