javascript - Checking if function exist in same scope when supplied the function name -

i've got format prototype method (simplified) , wanna check if char alphabetic (case insensitive), and if it's function declared in same scope. if is, want call function. if pass in x should execute alert.

i'm gonna using method format date given format string. e.g. format('h:i:s') check if h, i, , s function , call them.

how can achieve that?

i tried based on answer: https://stackoverflow.com/a/359910/1115367

here's code:

function time() {     //initialization }  time.prototype = {     format: function (char) {         if (char.test(/[a-z]/i) && typeof window[char] === 'function') { //undefined            window[char]();         }          function x() {             alert('works');         }     } }; 

if pass in value returns: uncaught typeerror: undefined not function

there no way retrieve local variables (or function) name (as far know anyway).

declared named functions assigned variable of same name: function thing(){} ~ var thing = function(){}

global variables automatically attached window can retrieve them name using window object.

however, (fortunately) not case other variables.

for example

var global1 = 'thing'; // root level (no wrapping function) -> global  (function(){     global2 = 'global';     // no 'var' keyword -> global variable (bad practice , not accepted in strict mode)     var local = 'whatever'; // local variable      function check(name){         if(window[name]) console.log('found: '+ name);         else console.log('nope: '+name);     }      check('foo');     check('global1');     check('global2');     check('local'); }()); 

will output:

[log] nope: foo [log] found: global1 [log] found: global2 [log] nope: local 

what can attach methods object.

edit

if option, can directly pass function argument (instead of string containing name).

function a(){}  function tocall(f){    // stuff f }  tocall(a);