How to get all functions and top-level names from Javascript

Something that is going to be tricky for you is that there are many different conventions for creating Javascript modules: putting variables in a global scope, returning a table from a file, etc. Module creation is also pretty dynamic so it might be easier to do things from inside Javascript.

Assuming you can get your hands in a javascript object corresponding to your module, you can inspect it with a for in loop:

var myModule = ...
for(var key in myModule){
  if( Object.hasOwnProperty.call(myModule, key) ){
    var func = myModule[key];
    ...
  }
}

To check if the object property is a function, you can use the typeof operator:

if(typeod func == "function")

and to see the number of arguments you can check the length property of the function:

func.length

Note that the number of arguments might be wrong if the function is variadic or otherwise gets arguments from the arguments array. But something checking the source text is also going to get that wrong...

It is possible to do it in node.js. Because of security reasons while runing a script with: node script.js one can not see functions or variables in global object provided by nodejs but while running a script with node -e "some script" one has access to functions and variables from global object.

So I wrote 3 scripts.

1. Reads the file that needs to be parsed (scriptThatNeedsToBeParsed.js) and the interpret file (interpretFile.js). Combines them and creates a process with node -e combinedFileContents
2. Script that needs to be parsed
3. Script used to interpret parsed file

scriptThatNeedsToBeParsed.js:

function A(a,b,c){}
var abc;
function T(){}

readFile.js:

I am reading the file that needs to be parsed and I define 2 variables: START_FROM_THIS_OBJECT before the content of the file and END_TO_THIS_OBJECT after the content of the file. So later I would know from where to where to search functions and variables.

if(process.argv.length !=4 )
{
    console.log("Usage %s <input-file> <interpret-file>",process.argv[0]);
    process.exit(0);
}
var input_file = process.argv[2];
var interpret_file = process.argv[3];
var fs = require('fs');
var fileToParse = ";var START_FROM_THIS_OBJECT;";
fileToParse += fs.readFileSync(input_file, "utf8");
var interpretFile = fs.readFileSync(interpret_file, "utf8");
fileToParse += ";var END_TO_THIS_OBJECT;";
var script = fileToParse + interpretFile;
var child = require('child_process').execFile('node', 
[ 
    '-e', script, 
], function(err, stdout, stderr) { 
    console.log(stdout); 
});

interpretFile.js: I search for functions and variables just "between" the 2 control variables defined above

var printObjects = false;
for(var item in global)
{
    if(item == "END_TO_THIS_OBJECT")
    {
        printObjects = false;
    }
    if(printObjects)
    {

        if(typeof(global[item]) == "function")
        {
            console.log("Function :%s with nr args: %d",item,global[item].length); 
        }
        else
        {
            console.log("Variable :%s with value: %d",item,global[item]); 
        }
    }
    if(item == "START_FROM_THIS_OBJECT")
    {
        printObjects = true;
    }
}

The last part of the global object from nodejs: console.log(global);

     module:
      { id: '[eval]',
        exports: {},
        parent: undefined,
        filename: 'E:\\LOCAL\\xampp\\htdocs\\nodejs\\[eval]',
        loaded: false,
        children: [],
        paths:
         [ 'E:\\LOCAL\\xampp\\htdocs\\nodejs\\node_modules',
           'E:\\LOCAL\\xampp\\htdocs\\node_modules',
           'E:\\LOCAL\\xampp\\node_modules',
           'E:\\LOCAL\\node_modules',
           'E:\\node_modules' ] },
     __dirname: '.',
     require:
      { [Function: require]
        resolve: [Function],
        main: undefined,
        extensions: { '.js': [Function], '.json': [Function], '.node': [Function] },
        registerExtension: [Function],
        cache: {} },
     START_FROM_THIS_OBJECT: undefined,<<<<<<<<<<<<<<
     A: [Function: A],
     abc: undefined,
     T: [Function: T],
     END_TO_THIS_OBJECT: undefined,<<<<<<<<<<<<<<<<

I run the script with : node readFile.js scriptThatNeedsToBeParsed.js interpretFile.js This is the output:
Function :A with nr args: 3
Variable :abc with value: NaN
Function :T with nr args: 0