当getter返回函数时，Firefox中出现意外行为

Question

Object.defineProperty(Number.prototype, 'foo', {
  get: function () {
    var me = this
    return function () { return me.valueOf() }
  }
})

console.log(5..foo())

This logs 5 in Chrome, but 0 in Firefox.

Object.defineProperty(Number.prototype, 'bar', {
  get: function () {
    return this.valueOf()
  }
})

console.log(5..bar)

This logs 5 in both browsers as expected.

Can anyone explain this behaviour, and perhaps suggest how the first example could be rewritten to work in Firefox as it does in Chrome?

jsfiddle.net/V2sHg/2/

Answer 1

It works for me on FF when using "new Number(value)" but not using directly a "number":

Try:

var n = new Number(8);
n.foo(); --> 8