code: function addOrEditProduct( list = [], newProduct ) {
  	let found = 0;
  	const products = list.map( product => {
  		if ( product.ID === newProduct.ID ) {
  			found = 1;
  			return newProduct;
  		}
  		return product;
  	} );
  	if ( ! found ) {
  		return [ newProduct, ...products ];
  	}
  	return products;
  }
docs: Edits existing product if one with matching ID found.
  Otherwise inserts the new one at the beginning of the list.
  @param {Array} list of previous products
  @param {Object} newProduct to update list with
  @returns {Array} updated array of products