code: function getDimension (collection, dimension) {
  		const first = collection[0];
  		if (first && typeof first.getBoundingClientRect === "function") {
  			return first.getBoundingClientRect()[dimension];
  		}
  	}
docs: Get the width or height of the first element in the collection
  @private
  @param {Jamon} collection - The Jamón instance
  @param {string} dimension - The dimension to get
  @return {(number|undefined)} - The result