Fix eslint error.
Fix eslint error.

Silverwolf90/vexflow,Huji/vexflow,Huji/vexflow,aaronmars/vexflow,Tails/vexflow,Silverwolf90/vexflow,aaronmars/vexflow,aaronmars/vexflow,Tails/vexflow,Huji/vexflow,Silverwolf90/vexflow,Tails/vexflow