How to get the function name from within that function

Question

How can I access a function name from inside that function        parasitic inheritance var ns parent child   function       var parent   new ns parent      parent newFunc   function            return parent     var ns parent   function          at this point  i want to know who the child is that called the parent      ie    var obj   new ns parent child

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You could use this  for browsers that support Error stack  not nearly all  probably   function WriteSomeShitOut       var a   new Error   stack match  at             console log a 1       WriteSomeShitOut      of course this is for the current function  but you get the idea   happy drooling while you code

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You can use name property to get the function name  unless you re using an anonymous function  For example    var Person   function Person        this someMethod   function            Person prototype getSomeMethodName   function        return this someMethod name      var p   new Person       will return     because someMethod is assigned with anonymous function console log p getSomeMethodName       now let s try with named function  var Person   function Person        this someMethod   function someMethod            now you can use      will return  someMethod  p getSomeMethodName

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look here  http   www tek-tips com viewthread cfm qid 1209619  arguments callee toString      seems to be right for your needs

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You could use Function name   In most implementations of JavaScript  once you have your constructor s reference in scope  you can get its string name from its name property  e g  Function name  or Object constructor name  You could use Function callee   The native arguments caller method has been deprecated  but most browsers support Function caller  which will return the actual invoking object  its body of code   https   developer mozilla org en-US docs Web JavaScript Reference Global Objects Function caller redirectlocale en-US amp redirectslug JavaScript 2FReference 2FGlobal Objects 2FFunction 2Fcaller  You could create a source map   If what you need is the literal function signature  the  name  of it  and not the object itself  you might have to resort to something a little more customized  like creating an array reference of the API string values you ll need to access frequently  You can map them together using Object keys   and your array of strings  or look into Mozilla s source maps library on GitHub  for bigger projects  https   github com mozilla source-map

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If I understood what you wanted to do  this is what I do inside a function constructor   if    this instanceof arguments callee         throw  ReferenceError      arguments callee name     is not defined

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what you re doing is assigning unnamed function to a variable  you probably need named function expression instead   http   kangax github com nfe      var x   function x         console log  arguments callee name      x      however I m not sure how much cross-browser that is  there s an issue with IE6 that makes you function s name leak to the outer scope  also  arguments callee is kind of deprecated and will result in error if you re using strict mode

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ES6  inspired by sendy halim s answer below    myFunction name   Explanation on MDN  As of 2015 works in nodejs and all major browsers except IE   Note  On bound functions this will give  bound  lt originalName gt    You will have to strip the  bound   if you want to get the original name     ES5  inspired by Vlad s answer    If you have a reference to the function  you can do   function functionName  func            Match         -            the beginning of the string        - function   the word  function         -  s         at least some white space        -    w       capture one or more valid JavaScript identifier characters        -  s         optionally followed by white space  in theory there won t be any here                      so if performance is an issue this can be omitted 1         -            followed by an opening brace            var result     function s    w      s     exec  func toString          return  result     result  1             for an anonymous function there won t be a match      I have not run unit tests on this  or verified implementation differences  but in principle it should work  if not leave a comment  Note  won t work on bound functions Note  that caller and callee are considered deprecated     1  I include it here because it is legal and often enough syntax highlighting tools fail to take into account the white space between function name and parenthesis  On the other hand  I m not aware of any implementation of  toString   that will include white space here  so that s why you can omit it     As an answer to the original question  I would drop parasitic inheritance and go for some more traditional OOP design patterns  I wrote a TidBits OoJs to comfortably write OOP code in JavaScript with a feature set mimicking C    not yet complete  but mostly    I see from the comments that you would like to avoid passing information parent needs to it s constructor  I must admit that traditional design patterns won t save you from that one though  since it is generally a considered a good thing to make your dependencies obvious and enforced   I would also suggest to steer away from anonymous functions  They only make debugging and profiling a PITA because everything just shows up as  anonymous function   and there is no benefit to them that I m aware of

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I had a similar problem and I solved it as follows   Function prototype myname   function        return this toString           substr  0  this toString   indexOf                  replace   function               This code implements  in a more comfortable fashion  one response I already read here at the top of this discussion  Now I have a member function retrieving the name of any function object  Here s the full script       lt script language  javascript  TYPE  text javascript  gt       Function prototype myname   function              return this toString                substr  0  this toString   indexOf                       replace  function                     function call this   fn     document write   fn myname            function  yeaaahhh        do something          call this   yeaaahhh       lt  script gt

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I know this is a old question but lately I ve been facing some similar issue while trying to decorate some React Component s methods  for debugging purposes  As people already said  arguments caller and arguments callee are forbidden in strict mode which is probably enabled by default in your React transpiling  You can either disable it  or I ve been able to come up with another hack  because in React all class functions are named  you can actually do this   Component prototype componentWillMount   function componentWillMount         console log  Callee name     this   proto   constructor toString   substr 0 30

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you can use Error stack to trace the function name and exact position of where you are in it   See stacktrace js

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Any constructor exposes a property name  which is the function name  You access the constructor via an instance  using new  or a prototype   function Person       console log this constructor name     Person    var p   new Person    console log p constructor name     Person  console log Person prototype constructor name      Person

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In ES6  you can just use myFunction name  Note  Beware that some JS minifiers might throw away function names  to compress better  you may need to tweak their settings to avoid that  In ES5  the best thing to do is  function functionName fun      var ret   fun toString      ret   ret substr  function   length     ret   ret substr 0  ret indexOf          return ret     Using Function caller is non-standard  Function caller and arguments callee are both forbidden in strict mode  Edit  nus s regex based answer below achieves the same thing  but has better performance

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It looks like the most stupid thing  that I wrote in my life  but it s funny  D function getName d     const error   new Error      const firefoxMatch    error stack split   n   0   d  match                    0     const chromeMatch       error stack split  at           1   d         match          lt           lt                  2         split      pop      const safariMatch   error stack split   n   0   d         firefoxMatch   console log  firefoxMatch   firefoxMatch    void 0       chromeMatch   console log  chromeMatch   chromeMatch    void 0       safariMatch   console log  safariMatch   safariMatch    void 0       return firefoxMatch    chromeMatch    safariMatch     d - depth of stack  0 - return this function name  1 - parent  etc    0   d  - just for understanding - what happens  firefoxMatch - works for safari  but I had really a little time for testing  because mac s owner had returned after smoking  and drove me away     Testing  function limbo      for let i   0  i  lt  4  i         console log getName i          function lust      limbo      function gluttony      lust       gluttony     Result  Chrome   Fitefox   This solution was creating only just for fun  Don t use it for real projects  It does not depend on ES specification  it depends only on browser realization  After the next chrome firefox safari update it may be broken  More than that there is no error  ha  processing - if d will be more than stack length - you will get an error  For other browsers error s message pattern - you will get an error  It must work for ES6 classes   split      pop     but you sill can get an error

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You can t  Functions don t have names according to the standard  though mozilla has such an attribute  - they can only be assigned to variables with names    Also your comment      access fully qualified name  ie  my namespace myFunc     is inside the function my namespace myFunc getFn  What you can do is return the constructor of an object created by new  So you could say   var obj   new my namespace myFunc    console info obj constructor     my namespace myFunc

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You can use constructor name like    your function  prototype constructor name   this code simply return name of a method

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This might work for you   function foo     bar       function bar     console log bar caller name       running foo   will output  foo  or undefined if you call from an anonymous function   It works with constructors too  in which case it would output the name of the calling constructor  eg  Foo     More info here  https   developer mozilla org en JavaScript Reference Global Objects Function Caller  They claim it s non-standard  but also that it s supported by all major browsers  Firefox  Safari  Chrome  Opera and IE

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as part as ECMAScript 6 you can use Function name method  function doSomething       alert doSomething name      alerts  doSomething

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Easy way to get function name from within fuction you are running    x000D   x000D  function x   alert this name   x   x000D   x000D   x000D

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This worked for me   function AbstractDomainClass         this className   function             if   this  className                var className   this constructor toString                className   className substr  function   length               className   className substr 0  className indexOf                    this  className   className                    return this  className            Test code    var obj   new AbstractDomainClass    expect obj className    toBe  AbstractDomainClass

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This will work in ES5  ES6  all browsers and strict mode functions   Here s how it looks with a named function    function myName       console log new Error   stack split   r n  r  n g  1  trim             at myName   lt anonymous gt  2 15    Here s how it looks with an anonymous function         gt      console log new Error   stack split   r n  r  n g  1  trim             at  lt anonymous gt  2 15

[javascript] How to get the function name from within that function?

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