AI solution for JavaScript Coding Question on BFE.dev
15. implement a simple DOM wrapper to support method chaining like jQuery

Sure, here's an implementation of the $ wrapper that supports chaining:

const $ = function(selector) {
  const elements = document.querySelectorAll(selector);
  
  // helper function to apply style to all elements
  const applyStyle = function(propertyName, value) {
    elements.forEach((element) => {
      element.style[propertyName] = value;
    });
    return this; // return this to enable chaining
  }
  
  return {
    css: applyStyle // expose the applyStyle function as css method
  };
};

// usage:
$('#button')
  .css('color', '#fff')
  .css('backgroundColor', '#000')
  .css('fontWeight', 'bold');

What this does is create a function $ that takes a CSS selector as input and returns an object with a single css method. The css method takes two arguments, a propertyName and a value, and sets that style for all elements matching the selector using the applyStyle helper function.

Importantly, applyStyle returns this, allowing the methods to be chained together. In this implementation, each call to $ creates a new object with its own applyStyle function, effectively isolating the chained calls from each other.

Hope that helps!