Utilizing ES6 Generator

I am going through Mozilla documentation about the Iterator and Generator concept introduced in ECMAScript6. Here is the overview as per Mozilla JS guide

Processing each of the items in a collection is a very common
operation. JavaScript provides a number of ways of iterating over a
collection, from simple for loops to map() and filter(). Iterators and
Generators bring the concept of iteration directly into the core
language and provide a mechanism for customizing the behavior of
for…of loops.

This post is not about how it works, it is better explained at Mozilla JS guide.

I have tried to apply the JS generator for one of the our day to day code. I think it is better suitable for lazy traversing and evaluating each item and proceed further if required. A common example comes in my mind is the tree traversing. I have implemented Depth First Search ( pre-order) using generator.

Consider the scenario where you need to traverse the tree node, evaluate/process the node and go further for next node. The code is as simple as below

var tree = getTree();
for (let node in tree.dfs()){
    // process node.
}

Isn’t above code super simple to understand, all traversing code it hidden, no need to manipulate the index/pointer etc.

Here I wrote simple traversing code that uses generator that return each node one by one.

function constructTree(values) {    
    return {
        dfs: function* (index) {
            if (!index) index = 0;
            yield values[index];
            if((2 * index + 1) < values.length)
                yield* this.dfs(2 * index + 1);
            if((2 * index + 2) < values.length)
                yield* this.dfs(2 * index + 2);

        }
    }
}

var tree = constructTree(values); 
for (let val of tree.dfs()) { 
   //process val
}

Here I am expecting the tree structure in an array. You can notice new syntax has been introduced function* to represent iterator/generator for the given JS object.

A generator is a special type of function that works as a factory for
iterators. A function becomes a generator if it contains one or more
yield expressions and if it uses the function* syntax.

The complete example is available at fiddle