externalUrlSlash cannot be updated#

In Canvas struct, there is a boolean externalUrlSlash. The value can be set when canvas is created, but there is no way to change it. Maybe this is intended, but based on that all other values can be updated, we assume that it should also be possible to update externalUrlSlash.

Recommendation#

Consider adding a way to update the externalUrlSlash. You can add canvas.externalUrlSlash = update.externalUrlSlash; to the end of updateCanvas function.