Immutable.js Map values to array

Question

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 ?

Can you give more details? Also I think you can give toJS a try. — Herrington Darkholme
– Herrington Darkholme, Commented Oct 15, 2015 at 12:45
jsfiddle, work for me. You even don't need the valueSeq. Could you create a sample to reproduce it? — fuyushimoya
– fuyushimoya, Commented Oct 15, 2015 at 12:45
try this: var array = [] mymap.valueSeq().forEach(function(item){ array.push(item)}) — javaguest
– javaguest, Commented Oct 15, 2015 at 12:45
@fuyushimoya you right - back to the drawing board for me to check - thanks — LenW
– LenW, Commented Oct 15, 2015 at 12:48
Oops, missed that, but then I believe it becomes a Collection of Map. Which means is.valueSeq().toArray() gives you an array of Map. You need to unwrap it further, like this. — fuyushimoya
– fuyushimoya, Commented Oct 15, 2015 at 13:41

Hüseyin Zengin · Accepted Answer · 2015-10-15 12:47:39Z

26

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

answered Oct 15, 2015 at 12:47

Hüseyin Zengin

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fuyushimoya · Accepted Answer · 2015-10-15 13:48:06Z

23

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>

answered Oct 15, 2015 at 13:48

fuyushimoya

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1 Comment

Dulguun Otgon Over a year ago

map.valueSeq().toArray() vs [...map.values()] which one is faster?

ericsoco · Accepted Answer · 2018-02-28 05:47:19Z

10

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()]

answered Feb 28, 2018 at 5:47

ericsoco

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2 Comments

trusktr Over a year ago

Are you talking about immutable.js Map, or ES6 Map?

ericsoco Over a year ago

Immutable.js. See the links in my answer. This does work with Immutable.js. @mjuopperi if you're finding otherwise, please clarify.

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