Converts style object into the corresponding CSS `style` attribute value

object-to-style-attribute.js

/**
 * Takes a style object and returns the corresponding 
 *     attribute value. Converts camel case property names
 *     to proper CSS selector names.
 * @param {Object} obj Map of CSS properties to values.
 * @return {string} The style attribute value.
 */
function toStyleAttribute = function(obj) {
  return Object.keys(obj).map(function(key) {
    
    // Camel case property names to CSS selector names.
    return (key.replace(/([A-Z])/g, '-$1').toLowerCase()) + 
        ':' + obj[key];

  }).join(';');
}