How To Read Values Within Arrays In Immutable.js

Question

Im a bit confused about this and cant seem to work this out.

Say I have this:

const AnObj = Immutable.Map({
 a : "a",
 b : Immutable.List.of(
  a,
  b,
  c,
  Immutable.Map({
   a : "a"
  })
 )
});

With Immutable Maps, we use strings within get() to find the corresponding properties. How do we read array values?

Answer 1

Disclaimer - This applies to all Immutable types, not just List.

Several ways -

1. The get method - AnObj.get('b').get(3).get('a') (Thanks @stas). This is useful when the structure is not very deep. As you see, the syntax is very verbose.

2. The succinct getIn - AnObj.getIn(['b', 3, 'a']) I love this because this pattern allows having a generic getter and I can toss the key-path around to the various components.

3. The veritable valueSeq/entrySeq, when you want all the values and don't care for indices - AnObj.get('b').valueSeq() This is useful when the list is huge and you want to delay the iteration until its absolutely needed. This is the most performant of them all.