var obj = { 0: 'a', 1: 'b', 2: 'c' }; // Creating an object with numerical properties. console.log(Object.getOwnPropertyNames(obj).sort()); // Logs the property names of obj sorted in ascending order. // Logging property names and values using Array.forEach Object.getOwnPropertyNames(obj).forEach(function(val, idx, array) { console.log(val + '->' + obj[val]); // Logs each property name and its corresponding value. }); // let's break down the `forEach` method and its parameters: // 1. **forEach**: // - `forEach` is a method available on arrays in JavaScript. // - It iterates over each element of the array and executes a provided function once for each element. // 2. **function(val, idx, array)**: // - Here, `function(val, idx, array)` is a callback function provided to `forEach`. // - This callback function is executed for each element in the array. // - It takes three parameters: // - `val`: The current value of the element being processed. // - `idx`: The index of the current element being processed. // - `array`: The array on which `forEach` was called (in this case, the array of property names obtained from the object). // So, when `Object.getOwnPropertyNames(obj).forEach(function(val, idx, array) {...})` is executed: // - `val` represents each property name of the object `obj` during iteration. // - `idx` represents the index of the current property name being iterated. // - `array` represents the array of property names obtained from `obj`. However, in this particular usage, it's not used because `array` represents the array on which `forEach` was called, and we are directly iterating over the property names of the object.