Fix to Safari Proxy bug

[bornajazvo]

Fixes occasional Safari bug that causes a break in Vue if using Set. There doesn't seem to be a reliable way to recreate it, closest I got was opening and closing dev tools while the app is loading but the timing is very strict and inconsistent.

This setup:

data() {
  return {
    foo: new Set(),
  }
},
mounted() {
  console.log(this.foo.size);
}

results in:

• First log: target, key, and receiver
• Second log: this
• Third log: target
• Errors

Seems like a Safari issue that on Reflect.get it turns the receiver Proxy into an object. Then it fails as target gets redefined assuming it’s a Proxy, and this returns undefined which errors when passed into Reflect.get.

This is the least disruptive fix to the bug, as we no longer rely on the Vue Proxy when checking size of Set.

[alecgibson]

Can you please bump the version?