The main issue is that "$(targetEl).append(h)" is not idempotent. This might seem like a small issue on the surface but as your application grows, this either

The main issue is that "$(targetEl).append(h)" is not idempotent. This might seem like a small issue on the surface but as your application grows, this either becomes a big problem or you have reinvented React, Vue, or something similar, but without the extensive testing and developer/community availability. Which is essentially what VSCode does for example, using some sort of MVP* pattern.