js 對象實現for of 遍歷 (defineProperty自定義功能)

1.對象
let myObject = {
    a: 2,
    b: 3
}

2.定制遍歷規則

Object.defineProperty(myObject, Symbol.iterator, {
    enumerable: false,
    writable: false,
    configurable: true,
    value: function () {
        let o = this
        let idx = 0
        let ks = Object.keys(o)
        return {
            next: function () {
                return {
                    value: o[ks[idx++]],
                    done: (idx > ks.length)
                }
            }
        }
    }
})

3.遍歷對象
for (let obj of myObject) {
    console.log(obj)
}