How to update element inside List with ImmutableJS?

Question

Here is what official docs said

updateIn(keyPath: Array<any>, updater: (value: any) => any): List<T>
updateIn(keyPath: Array<any>, notSetValue: any, updater: (value: any) => any): List<T>
updateIn(keyPath: Iterable<any, any>, updater: (value: any) => any): List<T>
updateIn(keyPath: Iterable<any, any>, notSetValue: any, updater: (value: any) => any): List<T>

There is no way normal web developer (not functional programmer) would understand that!

I have pretty simple (for non-functional approach) case.

var arr = [];
arr.push({id: 1, name: "first", count: 2});
arr.push({id: 2, name: "second", count: 1});
arr.push({id: 3, name: "third", count: 2});
arr.push({id: 4, name: "fourth", count: 1});
var list = Immutable.List.of(arr);

How can I update list where element with name third have its count set to 4?

Answer 1

The most appropriate case is to use both findIndex and update methods.

list = list.update(
  list.findIndex(function(item) { 
    return item.get("name") === "third"; 
  }), function(item) {
    return item.set("count", 4);
  }
); 

P.S. It's not always possible to use Maps. E.g. if names are not unique and I want to update all items with the same names.