Mastering Immutable.js

Parsing complex structures

The real power of the fromJS() function is its ability to turn complex JavaScript objects into complex immutable collections:

const myMap = fromJS({  a: {    b: ['c', 'd'],    e: {      f: 'g',      h: 'i'    }  }});console.log(  'myMap nested list',  myMap.getIn(['a', 'b']).toJS());// -> myMap nested list [ 'c', 'd' ]console.log('myMap nested value', myMap.getIn(['a', 'b', 1]));// -> myMap nested value d

The fromJS() function will recursively transform native JavaScript structures into their immutable counterparts; this means for both lists and maps. One use case for this function is when the initial data that your application uses is based on JSON data, and you need a way to translate it into Immutable.js collections. Without fromJS() ...