在 V8 JavaScript 中访问行号（Chrome 和 Node.js）
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Accessing line number in V8 JavaScript (Chrome & Node.js)
提问by james_womack
JavaScript developers who have spent time in languages like C often miss the ability to use certain types of introspection, like logging line numbers, and what method the current method was invoked from. Well if you're using V8 (Chrome, Node.js) you can employ the following.
花时间在像 C 这样的语言中的 JavaScript 开发人员经常错过使用某些类型的自省的能力，比如记录行号，以及调用当前方法的方法。好吧，如果您使用的是 V8（Chrome、Node.js），则可以使用以下内容。
回答by james_womack
Object.defineProperty(global, '__stack', {
get: function(){
var orig = Error.prepareStackTrace;
Error.prepareStackTrace = function(_, stack){ return stack; };
var err = new Error;
Error.captureStackTrace(err, arguments.callee);
var stack = err.stack;
Error.prepareStackTrace = orig;
return stack;
}
});
Object.defineProperty(global, '__line', {
get: function(){
return __stack[1].getLineNumber();
}
});
console.log(__line);
The above will log 19.
以上将登录19。
Combined with arguments.callee.calleryou can get closer to the type of useful logging you get in C via macros.
结合使用，arguments.callee.caller您可以更接近通过宏在 C 中获得的有用日志记录类型。
回答by alfasin
The problem with the accepted answer, IMO, is that when you want to print something you might be using a logger, and when that is the case, using the accepted solution will always print the same line :)
已接受的答案 IMO 的问题在于，当您想打印某些内容时，您可能会使用记录器，在这种情况下，使用已接受的解决方案将始终打印同一行:)
Some minor changes will help avoiding such a case!
一些小的改变将有助于避免这种情况！
In our case, we're using Winston for logging, so the codelooks like this (pay attention to the code-comments below):
在我们的例子中，我们使用 Winston 进行日志记录，因此代码如下所示（注意下面的代码注释）：
/**
* Use CallSite to extract filename and number, for more info read: https://v8.dev/docs/stack-trace-api#customizing-stack-traces
* @returns {string} filename and line number separated by a colon
*/
const getFileNameAndLineNumber = () => {
const oldStackTrace = Error.prepareStackTrace;
try {
// eslint-disable-next-line handle-callback-err
Error.prepareStackTrace = (err, structuredStackTrace) => structuredStackTrace;
Error.captureStackTrace(this);
// in this example I needed to "peel" the first CallSites in order to get to the caller we're looking for
// in your code, the number of stacks depends on the levels of abstractions you're using
// in my code I'm stripping frames that come from logger module and winston (node_module)
const callSite = this.stack.find(line => line.getFileName().indexOf('/logger/') < 0 && line.getFileName().indexOf('/node_modules/') < 0);
return callSite.getFileName() + ':' + callSite.getLineNumber();
} finally {
Error.prepareStackTrace = oldStackTrace;
}
};
