Not able to understand recursive behaviour in nested javascript object

Question

I am trying to understand how recursive work with a nested js object which may have same key name. For example in the below object the keys are same in nest. So when I am looping I am expecting obj[keys] will always go the first line(marked as //Line 1).

I am trying to understand how js will know consider which nest to loop if all the keys have same name. Not sure where I am going wrong in understanding

 var obj = { a: { // Line 1 a: { // Line 2 a: { // Line 3 sweptArea: 5 } } } } function loop(obj, keyName) { for (var keys in obj) { if (obj.hasOwnProperty(keys) && typeof obj[keys] === 'object') { if (obj[keys][keyName] !== undefined) { console.log(obj[keys][keyName]) } else { // In my understanding in all the iteration it will point to obj.a marked as line one loop(obj[keys], 'sweptArea') } } } } loop(obj, 'sweptArea') 

Answer 1

When you say obj[keys] is only looks for a key of that name on obj . That expression, by itself, does no recursion.

The value passed to the variable defined to the obj argument is different each time the function is called.