I agree, but its the ONLY way I could get the spritesheets to switch between each frame. Without doing this way, the sprite goes into an endless loop. What this is doing is just switching between the arms moving back and forth.
canvasIDList is an array containing our canvas ID's and is located in world.js with the other global variables. That is where it is initialized. Doing this requires us just to change that config array verses every location of that ID name. Much cleaner.