javascript - 遍历arguments.callee.caller会导致无限循环

Question

假设我想获取某种堆栈跟踪，获取当前函数之前调用的所有函数的名称。

我做了这样的事情:

        var callee;
        var caller;
        var _args = arguments;
        var check = 0;
        do {
                    check++;

                    callee = _args.callee;
                    caller = callee.caller;

                    var msg = 'Check ' + check + ' - ' + callee.name 
                            + ' has been called by: ' + caller.name;
                    console.log(msg);

                    if (caller) {
                        // Get this caller's arguments
                        _args = caller.arguments;
                    } else {
                        reached_end = true;
                    }

        } while (!reached_end);

大多数情况下，这都可以正常工作。但有时它会陷入无限循环，我想知道:这怎么可能？我能做些什么呢？

这是我的无限循环的输出:

    Check 1 - __parent__ has been called by: add
    Check 2 - add has been called by: afterComponentStartup
    Check 3 - afterComponentStartup has been called by: _launchComponents [arg0:"startup"]
    Check 4 - _launchComponents has been called by: beforeActionNext
    Check 5 - beforeActionNext has been called by: beforeAction
    Check 6 - beforeAction has been called by: afterComponentInitialize
    Check 7 - afterComponentInitialize has been called by: _launchComponents [arg0:"startup"]
    Check 8 - _launchComponents has been called by: beforeActionNext
    Check 9 - beforeActionNext has been called by: beforeAction
    Check 10 - beforeAction has been called by: afterComponentInitialize
    Check 11 - afterComponentInitialize has been called by: _launchComponents [arg0:"startup"]
    Check 12 - _launchComponents has been called by: beforeActionNext
    Check 13 - beforeActionNext has been called by: beforeAction
    Check 14 - beforeAction has been called by: afterComponentInitialize
    Check 15 - afterComponentInitialize has been called by: _launchComponents [arg0:"startup"]
    Check 16 - _launchComponents has been called by: beforeActionNext
    Check 17 - beforeActionNext has been called by: beforeAction
    Check 18 - beforeAction has been called by: afterComponentInitialize
    Check 19 - afterComponentInitialize has been called by: _launchComponents [arg0:"startup"]
    Check 20 - _launchComponents has been called by: beforeActionNext
    Check 21 - beforeActionNext has been called by: beforeAction
    Check 22 - beforeAction has been called by: afterComponentInitialize
    Check 23 - afterComponentInitialize has been called by: _launchComponents [arg0:"startup"]
    Check 24 - _launchComponents has been called by: beforeActionNext
    Check 25 - beforeActionNext has been called by: beforeAction
    Check 26 - beforeAction has been called by: afterComponentInitialize

Answer 1

arguments.callee.caller 指向函数引用，每个调用堆栈中每个函数只存在一个函数引用。

每次调用函数时，都会设置caller属性，这意味着如果在调用堆栈中多次调用同一个函数(就像递归函数一样)，则先前的值将被重置，并且caller现在将指向其自身。这就是导致无限循环的原因。

因此，在您的算法中，如果您到达 callee === callee.caller 的点，您需要中断以避免这种情况发生。