fix: use drop valueOf when evaluated as condition (#705)

src/render/boolean.ts

@@ -1,10 +1,13 @@
 import { Context } from '../context/context'
+import { toValue } from '../util'
 
 export function isTruthy (val: any, ctx: Context): boolean {
   return !isFalsy(val, ctx)
 }
 
 export function isFalsy (val: any, ctx: Context): boolean {
+  val = toValue(val)
+
   if (ctx.opts.jsTruthy) {
     return !val
   } else {