I have a function:
fs.readFile = function(filename, callback) {
// implementation code.
};
Sometime later I want to see the signature of the function during debugging.
When I tried console.log(fs.readFile) I get [ FUNCTION ], which does not give me any information.
How can I get the signature of the function?
Call .toString() on the function:
$ node
> foo = function(bar, baz) { /* some code */ }
[Function: foo]
> foo
[Function: foo]
> foo.toString()
'function(bar, baz) { /* some code */ }'
or use a shortcut like foo+"".
If what you mean by "function signature" is how many arguments it has defined, you can use:
function fn (one) {}
console.log(fn.length); // 1
All functions get a length property automatically.
I am not sure what you want but try looking at the console log of this fiddle, it prints entire function definition. I am looking at chrome console.log output.
var fs = fs || {};
fs.readFile = function(filename, callback) {
alert(1);
};
console.log(fs.readFile);
fs.readFile: nodejs.org/api/fs.html#fs_fs_readfile_filename_options_callbackfunctionname.toString().match(/function\s*(.*?)\s*{/)[1]