尝试递归调用同步函数来解析数组中的元素;一旦到达数组的最后一个元素,就会调用回调。但是在传递给process时,回调被认为是未定义的。nextTick作为另一个变量,在与回调函数相同的作用域中声明,输出正确的值。
有谁能解释我做错了什么吗?当同一作用域内的另一个变量被正确访问时,回调如何未定义呢?
someobject.prototype.launch = function (callback) {
if (!this.config.children || this.config.children.length <= 0)
throw new Error('No children found');
var callCounter = 1;
var _callback = function () {
callback(true)
};
console.log(_callback); // prints [Function] as expected
function create(i) {
//some logic to process
//the 'i' element
if (callCounter == stopAt) {
var _callback = callback(true);
//process.nextTick(_callback); //this too doesnt work as _callback is undefined
process.nextTick(function () {
console.log(callCounter + ' ' + _callback);
// the callback is undefined where as callCounter holds the proper value.
});
}else {
//process.nextTick( (create.bind(this))(callCounter++));
(create.bind(this))(callCounter++)
}
(create.bind(this))(0);
}
var _callback = callback(true);
这个字符串可以返回未定义的值。你是否同意回调(true)返回其他函数或值。删除或评论
未定义函数result示例
var func_without_result = function(){};
console.log(func_without_result());
结果> undefined