How do I print a stack trace from JavaScript?
The answer How can I get a Javascript stack trace when I throw an exception? deals with throwing an exception, but I need to print stack traces to debug a memory leak.
Basically I've got the same question as Get current stack trace in Java but for JavaScript.
And How to print a stack trace in Node.js? is similar but it's Node.js and I want to know for JavaScript, more generally speaking, if it's different.
This line of code gets a stack trace and prints it:
console.trace();
Source: https://developer.mozilla.org/en-US/docs/Web/API/Console/trace
console.trace() is the default correct answer in absence of additional details along the lines of "how do I do X in this highly niche, super-legacy JS engine".
var currentStackTrace = /* what code here ? */
stack field on Error, for example var currentStackTrace = Error().stack.substring(6).split(" at ") sets currentStackTrace to an array of strings where each string is a line in the stack.print() call from that.
Error().stack is the better answer because it's more general. It lets you do everything this answer does and more.You can get stack trace by creating error and printing its stack property.
var stackTrace = Error().stack;
console.log(stackTrace); // if console.log is available
alert(stackTrace); // ditto
var xhr = new XMLHttpRequest(); xhr.open(...); xhr.send(stackTrace); // submit to server
// or do whatever else with the variable
This unlike console.trace() works in all cases, even if console class is not available in your environment. (Of course, if print is not available, you can use console.log or any other function for printing which you have in your environment).
print is beside point here. It is just an example. Error().stack is important part. Beside, question asker has stated in his question that he wants more general than node.js answer. So context is not limited to node.js. More generally than node.js you do it by Error().stack and printing its output with whatever function you have available. Error().stack will work in any JavaScript version, while console.trace() will not. Plus, you can make print work in node.js if you do: print=console.log.console.trace(), whereas your answer shows code that won't work in any browser, nor in Node.js - if you want to mention new Error().stack then by all means add that as second part to your answer. As it stands, your answer as posted does not work in any common JS engine, and as such is a bad answer. Remember why SO exists in the first place: if the answer has code that code should work
print isn't important. Actually, this answer is better than the accepted one, because console.trace() can ONLY output it to the console, whereas Error().stack gives you options - submit to server, etc.The documentation says it could be done in the following way:
const targetObject = {};
Error.captureStackTrace(targetObject);
targetObject.stack; // Similar to `new Error().stack`
This code snippet creates a .stack property on targetObject, which when accessed returns a string representing the location in the code at which Error.captureStackTrace() was called.
stackTracefunction in the accepted answer? It boils down tovar e = new Error(); console.log(e.stack)