Question

194

Get name and line of calling function in node.js

rated 0 times [ 197] [ 3] / answers: 1 / hits: 77404 / 12 Years ago, sat, january 5, 2013, 12:00:00

How can one get the name and line of a function that called the current one? I would like to have a rudimentary debugging function like this (with npmlog defining log.debug):

function debug() {

  var callee, line;

  /* MAGIC */

  log.debug(callee + : + line, arguments)

}

When called from another function it would be something like this:

function hello() {

   debug(world!)

}

// outputs something like:

// hello:2 'world!'

For clarity, what I want is essentially analogous to this in Python:

import inspect

def caller():

    return inspect.stack()[2][3]

// line no from getframeinfo().lineno

Is there a Node equivalent to accomplish this?

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elliem

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2 Years ago

answered 12 Years ago yaquelina · Accepted Answer

Using info from here: Accessing line number in V8 JavaScript (Chrome & Node.js)

you can add some prototypes to provide access to this info from V8:

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();

    }

});



Object.defineProperty(global, '__function', {

get: function() {

        return __stack[1].getFunctionName();

    }

});



function foo() {

    console.log(__line);

    console.log(__function);

}



foo()

Returns '28' and 'foo', respectively.