Question

我正在尝试包装process.nextTick函数，但这会导致递归。

var actual = process.nextTick;

process.nextTick = function(callback)
{
console.log('next tick called');
actual.apply(this, arguments);
}

console.log('starts');
setTimeout(function(){
console.log('set timeout called');
}, 100);

此代码生成

starts
next tick called
next tick called
...
RangeError: Maximum call stack size exceeded

任何人都可以解释工作流程吗？

Answer 1

我非常确定console.log()正在调用process.nextTick()并导致递归。

查看以下示例：

var counter = 0;
var actual = process.nextTick;

process.nextTick = function ()
{
    counter++;
    actual.apply(this, arguments);
}

console.log('starts ...'); // This will increment counter with 1, counter = 1
process.nextTick(function () {
    console.log('nextTick callback'); // This will increment counter with 1, counter = 3
    console.log(counter); // This will increment counter with 1, counter = 4
});
console.log('something else ...'); // This will increment counter with 1, counter = 2

/*
 *   OUTPUT 
 */
starts ...
something else ...
nextTick callback
4

现在，如果我们删除其中一个console.log()来电，我们可以看到以下内容：

var counter = 0;
var actual = process.nextTick;

process.nextTick = function ()
{
    counter++;
    actual.apply(this, arguments);
}

console.log('starts ...'); // This will increment counter with 1, counter = 1
process.nextTick(function () {
    console.log(counter); // This will increment counter with 1, counter = 3
});
console.log('something else ...'); // This will increment counter with 1, counter = 2

/*
 *   OUTPUT 
 */
starts ...
something else ...
3

请注意，计数器现在 3 。

所以我的结论是console.log()内部process.nextTick()覆盖函数导致了递归。

我希望这个例子可以帮助你清除这些事情：）

wrap process.nextTick导致超出最大调用堆栈大小

1 个答案: