What's missing?

I am not getting solution

const {length:len} =str.length; // change this
// change code above this line

return len; // you must assign length to len in line

Right side have to contain just name of an object that inludes required property without the property name.
For example:

const obj = {apples: 10};
const {apples: eat} = obj;
console.log(eat);// 10

even your logic doesnt work

const length = {x:str.length}; // change this
const {x:len} = length;

Ok. Here is construction.
const {} = obj;
You declare const first and then you assign the obj to it.
Second step.
Within your const object on the left side you have to use next syntax:
const { x : y } where x is the property of the existing object and y is a name of your own variable.
Well we have next syntax:
const { x : y } = obj;

thats what i have done.

still its not working

This is your code:

const {length:len} =str.length; // change this
// change code above this line

Try to change str.length to str

like this…doesnt work
var str =str.length + 0;
const {length:len} =str;

Why are you doing it? Delete this line and try again.

works…but how??? whr that lenth gets calculated??

We did it bro. Congrats.

Now about length.
Every string in JavaScript has its own property like length.

I suggest you to read next articles:

  1. MDN: Objects
    2.W3C: String
    3.W3C: String Property - length

You have to understand what is the string in JS.
WTG! Keep going.

thanks mate. what do you do btw?