Editing closures vs eval scope passage

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while i was looking for a ways to initialize data modules

in v8 javascript engine there is scope.close() when you develop v8 native modules. it happens at each end of function to let pass variables on while maintaining scope. also when you do eval it makes like a new file.js with evaled code and append it to running code

suppose a simple function that should be dynamically constructed for different tables and i wanted to have same performance in dynamic as in hand typed.

will it run faster with closures or with evaled function

```
app.put('/api/users/:id', function(req, res)
{
	var data = req.body;
	db.query(
		'UPDATE users '+
		'SET username = ?, password = ?  where _id = ?',
		[data.username   , data.password,     req.params.id],
		function(err, results, fields) {
			var insertId = results.insertId
			data._id = insertId;
			res.send(JSON.stringify(data));
		}
	);
});
```

conclusions:

to get fast execution put all code in one js file

it is worth it after doing eval to copy functions to local scope

it is good only if it copied totally, if there is even a one function or a variable dating back to another scope it slows down twice.

also it is good only if the code evaled in the same scope otherwise it slows down

firefox slightly slower then v8(chrome)  but firefox has only a tiny bit of scope passage slow down or no scope passage slow down at all.

test 4 and test 8 actually work

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Preparation code

Preparation code HTML (this will be inserted in the <body> of a valid HTML5 document in standards mode) (useful when testing DOM operations or including libraries)

Include JavaScript libraries as follows: <script src="//cdn.ext/library.js"></script>

Define setup for all tests (variables, functions, arrays or other objects that will be used in the tests) (runs before each clocked test loop, outside of the timed code region) (e.g. define local test variables, reset global variables, clear canvas, etc.) (see FAQ)

function query()
{
 return Math.random();
}

function test1()
{
  var data={username:'aaa',password:'vvv',_id:1}
  query(
		'UPDATE users '+
		'SET username = ?, password = ?  where _id = ?',
		[data.username   , data.password,  1],
		function(err, results, fields) {
		}
	);
}

function strreplacefn(fn,replacefromtoarr)
{
 var s=fn.toString();
 for(var i=0;i<replacefromtoarr.length;i++)
 {
  s=s.split(replacefromtoarr[i][0]).join(replacefromtoarr[i][1]);
 }
 return s;
}

//replace something whatether and make new function from eval
eval(strreplacefn(test1,[['function '+test1.name+'(','function test3('],
                              ['username','myusername'],
                              ['password','mypassword']]))
var test4=test3;

//try adding a function dating back to evaled scope
eval('function piggyback_fn(){return Math.random();};'+
strreplacefn(test1,[['function '+test1.name+'(','function test5_('],
                              ['username','myusername'],
                              ['password','mypassword'],
                              ['query(','piggyback_fn();query(']
]))
var test5=test5_;

//try to make a function that does all together
function strreplacefn1(fn,replacefromtoarr,optnewname)
    {
     var s=fn.toString();
     //optnewname=optnewname||fn.name||'fn'
     optnewname='fn'
     replacefromtoarr.push(['function '+fn.name+'(','function '+optnewname+'('])
     for(var i=0;i<replacefromtoarr.length;i++)
     {
      s=s.split(replacefromtoarr[i][0]).join(replacefromtoarr[i][1]);
     }
     eval(s)
     //return {fn:eval(optnewname)};
     return fn;
    }

var test6=strreplacefn1(test1,[['username','myusername'],
                              ['password','mypassword']])

//try to make a function that does all together2
function strreplacefn2(fn,replacefromtoarr,optnewname)
    {
     var s=fn.toString();
     optnewname=optnewname||fn.name||'fn'
     //optnewname='fn'
     replacefromtoarr.push(['function '+fn.name+'(','function '+optnewname+'('])
     for(var i=0;i<replacefromtoarr.length;i++)
     {
      s=s.split(replacefromtoarr[i][0]).join(replacefromtoarr[i][1]);
     }
     return s+';'+optnewname;
    }

var test7=eval(strreplacefn2(test1,[['username','myusername'],
                              ['password','mypassword']],'test7_'));

//try to make a function that does all together3
function strreplacefn3(fn,replacefromtoarr,optnewname)
    {
     var s=fn.toString();
     optnewname=optnewname||fn.name||'fn'
     //optnewname='fn'
     replacefromtoarr.push(['function '+fn.name+'(','function '+optnewname+'('])
     for(var i=0;i<replacefromtoarr.length;i++)
     {
      s=s.split(replacefromtoarr[i][0]).join(replacefromtoarr[i][1]);
     }
     return s;
    }

eval(strreplacefn3(test1,[['username','myusername'],
                              ['password','mypassword']],'test8'));
var test8=test8;// copy to current scope

Title

Async (check if this is an asynchronous test)

Code

test9()