sometime select's event does't work when option's vlaue in ('',0)

Vue.js version

2.1.6

Reproduction Link

http://sandbox.runjs.cn/show/xu7gfzz2

Steps to reproduce

switch tag option between value=‘’ and value=‘0’, then to see {{ selected }}'s change.

What is Expected?

the value of ‘selected’ always changes with your choose.

What is actually happening?

sometime works, sometime does’t work.

[defcc]

Campares fails in looseEqual, I’ll make a patch.

[rpkilby]

@LinusBorg testing on chrome 56/OS X, I can verify that the fiddle is broken (whether or not it’s Vue or the fiddle’s fault, not sure).

1. The select is initialized with “on” and the text displays “Selected: 1”.
2. Select “off”.
   • Expected the selected option to be “off”, text should display “Selected: 0”.
   • Selected option was the empty choice, text correctly displays “Selected: 0”.
3. Select “off” again (since it’s currently empty).
   • The “off” option is correctly selected, text correctly displays “Selected: 0”.
4. Select the empty choice.
   • The empty choice is correctly selected, text correctly displays "Selected: ".
5. Select “off”. Even though the current choice is empty, this breaks again.
   • Expected the selected option to be “off”, text should display “Selected: 0”.
   • Selected option was the empty choice, text correctly displays “Selected: 0”.
6. Select “off” again (since it’s currently empty).
   • The “off” option is correctly selected, text correctly displays “Selected: 0”.

I was able to fix the fiddle in two ways:

• change the numeric values to strings.
• change the ‘empty’ option to a number (such as -1).

Either vue is getting confused by having two falsey values (‘’, 0), or vue is getting confused by the mixed types.