编辑代码

// arguments是获取函数参数的数组列表
// arguments[0]是第一个参数值
function* idMaker() {
    var index = arguments[0] || 0
    while (true) {
        yield index++
    }
}

var gen = idMaker(5)
console.log(gen.next())
console.log(gen.next())
console.log(gen.next())
console.log(gen.next())
console.log(gen.next())
console.log(gen.next())