It was a time to see how it differs from the existing js and jquery methods while implementing the todo app with vue, and it was good that it explained well how the code was simplified step by step. However, I was a little disappointed that the implemented todo app seemed to be made with code that was easy for beginners to read, so I changed the function and the way data was saved and implemented it. I saved it in local storage so that I could manage the todo list with one array. I thought that the key value should not be duplicated, so I increased the count by checking for duplicates. Separately added functions include filtering, count, menu bar, and theme change. The added functions were referenced from the example on the official website. https://vuejs.org/v2/examples/todomvc.html