Can I get the name of the currently running function in JavaScript

Question

Is it possible to do this   myfile js  function foo         alert  lt my-function-name gt           pops-up  foo         or even better   myfile js   foo      I ve got the Dojo and jQuery frameworks in my stack  so if either of those make it easier  they re available

User · Answer

An updated answer to this can can be found over at this answer: https://stackoverflow.com/a/2161470/632495

and, if you don't feel like clicking:

function test() {
  var z = arguments.callee.name;
  console.log(z);
}

User · Answer

Try   alert arguments callee toString

User · Answer

The name of the current function and how it can be obtained seems to have changed over the past 10 years  since this question was asked    Now  not being a pro web developer who knows about all the histories of all browsers ever having existed  here is how it works for me in a 2019 chrome browser   function callerName         return callerName caller name    function foo         let myname   callerName           do something with it        Some of the other answers ran into some chrome errors about strict javascript code and whatnot

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function f         console log f name      logs f         Typescript variation   function f1       function f2 f Function       console log f name      f2 f1      Logs f1   Note only available in ES6 ES2015 compliant engines   For more see

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For non-anonymous functions   function foo          alert arguments callee name      But in case of an error handler the result would be the name of the error handler function  wouldn t it

User · Answer

This should do it   var fn   arguments callee toString   match  function s     s         alert fn 1      For the caller  just use caller toString

User · Answer

Another use case could be an event dispatcher bound at runtime   MyClass   function        this events             Fire up an event  most probably from inside an instance method    this OnFirstRun          Fire up other event  most probably from inside an instance method    this OnLastRun        MyClass prototype dispatchEvents   function        var EventStack this events GetFunctionName     i EventStack length-1     do EventStack i       while  i--      MyClass prototype setEvent   function  event  callback      this events event          this events event  push callback     this  On  event    this dispatchEvents     MyObject   new MyClass    MyObject setEvent   FirstRun   somecallback   MyObject setEvent   FirstRun   someothercallback   MyObject setEvent   LastRun   yetanothercallback     The advantage here is the dispatcher can be easily reused and doesn t have to receive the dispatch queue as an argument  instead it comes implicit with the invocation name     In the end  the general case presented here would be  using the function name as an argument so you don t have to pass it explicitly   and that could be useful in many cases  such as the jquery animate   optional callback  or in timeouts intervals callbacks   ie you only pass a funcion NAME

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A combination of the few responses I ve seen here    Tested in FF  Chrome  IE11   function functionName         var myName   functionName caller toString       myName   myName substr  function   length      myName   myName substr 0  myName indexOf           return myName     function randomFunction        var proof    This proves that I found the name      functionName              alert proof       Calling randomFunction   will alert a string that contains the function name   JS Fiddle Demo  http   jsfiddle net mjgqfhbe

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This has to go in the category of  world s ugliest hacks   but here you go   First up  printing the name of the current function  as in the other answers  seems to have limited use to me  since you kind of already know what the function is   However  finding out the name of the calling function could be pretty useful for a trace function   This is with a regexp  but using indexOf would be about 3x faster   function getFunctionName         var re    function              var s   getFunctionName caller toString        var m   re exec  s       return m 1      function me         console log  getFunctionName         me

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The getMyName function in the snippet below returns the name of the calling function  It s a hack and relies on non-standard feature  Error prototype stack  Note that format of the string returned by Error prototype stack is implemented differently in different engines  so this probably won t work everywhere    x000D   x000D  function getMyName     x000D    var e   new Error  dummy    x000D    var stack   e stack x000D                   split   n   2  x000D                       at functionName          gt   functionName  x000D                   replace    s at s       s   g    1     x000D                  return stack x000D    x000D   x000D  function foo    x000D    return getMyName   x000D    x000D   x000D  function bar     x000D    return foo   x000D    x000D   x000D  console log bar    x000D   x000D   x000D    About other solutions  arguments callee is not allowed in strict mode and Function prototype calleris non-standard and not allowed in strict mode

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Information is actual on 2016 year     Results for function declaration  Result in the Opera   gt  gt  gt   function func11             console log               Function name                arguments callee toString   match  function s     w      1                       function func12             console log  Function name    arguments callee name            Function name   func11 Function name   func12   Result in the Chrome   function func11         console log           Function name            arguments callee toString   match  function s     w      1           function func12         console log  Function name    arguments callee name        Function name  func11 Function name  func12   Result in the NodeJS   gt   function func11             console log                 Function name                  arguments callee toString   match  function s     w      1             Function name  func11 undefined  gt   function func12             console log  Function name    arguments callee name            Function name  func12   Does not work in the Firefox  Untested on the IE and the Edge     Results for function expressions  Result in the NodeJS   gt  var func11   function            console log  Function name    arguments callee name         func11    Function name  func11   Result in the Chrome  var func11   function        console log  Function name    arguments callee name     func11    Function name  func11   Does not work in the Firefox  Opera  Untested on the IE and the Edge   Notes    Anonymous function does not to make sense to check  Testing environment         google-chrome --version Google Chrome 53 0 2785 116                opera --version Opera 12 16 Build 1860 for Linux x86 64      firefox --version Mozilla Firefox 49 0     node node    nodejs       nodejs --version v6 8 1     uname -a Linux wlysenko-Aspire 3 13 0-37-generic  64-Ubuntu SMP Mon Sep 22 21 28 38 UTC 2014 x86 64 x86 64 x86 64 GNU Linux

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All what you need is simple  Create function   function getFuncName        return getFuncName caller name     After that whenever you need  you simply use   function foo        console log getFuncName       foo       Logs   foo

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Here s a way that will work   export function getFunctionCallerName          gets the text between whitespace for second part of stacktrace   return  new Error    stack match  at   S   g  1  slice 3       Then in your tests   import   expect   from  chai   import   getFunctionCallerName   from           lib util functions    describe  Testing caller name        gt         it  should return the name of the function        gt          function getThisName            return getFunctionCallerName                   const functionName   getThisName           expect functionName  to equal  getThisName               it  should work with an anonymous function        gt          const anonymousFn   function           return getFunctionCallerName                const functionName   anonymousFn         expect functionName  to equal  anonymousFn             it  should work with an anonymous function        gt        const fnName    function           return getFunctionCallerName                   expect    util  functions  js  test fnName   to eql true                Note that the third test will only work if the test is located in  util functions

User · Answer

The answer is short  alert arguments callee name

User · Answer

This a variant of Igor Ostroumov s answer   If you would like to use it as a default value for a parameter  you need to consider a second level call to  caller    function getFunctionsNameThatCalledThisFunction       return getFunctionsNameThatCalledThisFunction caller caller name      This would dynamically allow for a reusable implementation in multiple functions    x000D   x000D  function getFunctionsNameThatCalledThisFunction   x000D    x000D    return getFunctionsNameThatCalledThisFunction caller caller name  x000D    x000D   x000D  function bar myFunctionName   getFunctionsNameThatCalledThisFunction    x000D     x000D    alert myFunctionName   x000D    x000D   x000D     pops-up  foo  x000D  function foo   x000D    x000D    bar    x000D    x000D   x000D  function crow   x000D    x000D    bar    x000D    x000D   x000D  foo    x000D  crow    x000D   x000D   x000D    If you want the file name too  here is that solution using the answer from F-3000 on another question   function getCurrentFileName       let currentFilePath   document scripts document scripts length-1  src    let fileName   currentFilePath split      pop      formatted to the OP s preference    return fileName     function bar fileName   getCurrentFileName     myFunctionName   getFunctionsNameThatCalledThisFunction        alert fileName           myFunctionName         or even better   myfile js   foo  function foo       bar

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According to MDN      Warning  The 5th edition of ECMAScript  ES5  forbids use of arguments callee   in strict mode  Avoid using arguments callee   by either giving function expressions a name or use a function declaration where a function must call itself    As noted this applies only if your script uses  strict mode    This is mainly for security reasons and sadly currently there s no alternative for this

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Here is a one liner       arguments callee toString   split   n   0  substr  function   length  replace             replace   r         Like this       function logChanges           let whoami   arguments callee toString   split   n   0  substr  function   length  replace             replace   r              console log whoami      just getting started

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Since you have written a function named foo and you know it is in myfile js why do you need to get this information dynamically   That being said you can use arguments callee toString   inside the function  this is a string representation of the entire function  and regex out the value of the function name   Here is a function that will spit out its own name   function foo         re     function s              alert re exec arguments callee toString    1

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In ES5 and above  there is no access to that information   In older versions of JS you can get it by using arguments callee   You may have to parse out the name though  as it will probably include some extra junk   Though  in some implementations you can simply get the name using arguments callee name   Parsing   function DisplayMyName         var myName   arguments callee toString       myName   myName substr  function   length      myName   myName substr 0  myName indexOf            alert myName          Source  Javascript - get current function name

[javascript] Can I get the name of the currently running function in JavaScript?

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