In strict mode you can no longer reference callee (see the related discussion at Javascript: is the arguments array deprecated?) You might want to post a new question where you can illustrate your, This is not exactly a "proper" way, so I am not posting it as an answer, bit it might be good enough for debugging. To make enable strict mode for the entire code in a single JS file, add "use strict" as the first line of code. Write "use strict" at the top of JavaScript code or in a function. Duplicating a parameter name is not allowed: Writing to a read-only property is not allowed: Writing to a get-only property is not allowed: Deleting an undeletable property is not allowed: The word eval cannot be used as a variable: The word arguments cannot be used as a variable: For security reasons, eval() is not allowed to create How to get JS class name from class, but not from instance? On what basis are pardoning decisions made by presidents or governors when exercising their pardoning power? Given a function and the task is to get the name of function that is currently running using JavaScript. A minor scale definition: am I missing something? Source: Javascript - get current function name. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. Accessing a property on a primitive implicitly creates a wrapper object that's unobservable, so in sloppy mode, setting properties is ignored (no-op). Content Discovery initiative April 13 update: Related questions using a Review our technical responses for the 2023 Developer Survey. It helps you to write cleaner code, How to print and connect to printer using flutter desktop via usb? SyntaxError: Unexpected '#' used outside of class body, SyntaxError: unlabeled break must be inside loop or switch, SyntaxError: unparenthesized unary expression can't appear on the left-hand side of '**', SyntaxError: Using //@ to indicate sourceURL pragmas is deprecated. Why Is PNG file with Drop Shadow in Flutter Web App Grainy? How a top-ranked engineering school reimagined CS curriculum (Ep. And arguments.callee.caller.name not working either (nodejs v7.5.0). I would like to have a rudimentary debugging function like this (with npmlog defining log.debug ): 6 1 function debug() { 2 var callee, line; 3 /* MAGIC */ 4 log.debug(callee + ":" + line, arguments) 5 } 6 When called from another function it would be something like this: In strict mode, it is now undefined. Oh that's why people always beat me on the speed to reply. "use strict" is just a string, so IE 9 will not throw an error even if it does not understand it. Unexpected uint64 behaviour 0xFFFF'FFFF'FFFF'FFFF - 1 = 0? Using Strict mode for the entire script: To invoke strict mode for an entire script, put the exact statement use strict; (or use strict;) before any other statements. Get current function name in strict mode I need the current function name as a string to log to our log facility. Strict mode removes most cases where this happens, so the compiler can better optimize strict mode code. JavaScript code should be executed in Prohibits some syntax likely to be defined in future versions of ECMAScript. JSLint is suddenly reporting: Use the function form of "use strict". Btw, I am using VisualStudio Code and havent look at automatic refactoring tools for JavaScript. JavaScript strict mode "use strict" "use strict" JavaScript 1.8.5 (ECMAScript5) JavaScript "use strict" : Internet Explorer 10 +Firefox 4+ Chrome 13+ Safari 5.1+ Opera 12+ use strict; Get certifiedby completinga course today! I still would like to have a way to reference the name of the current function just for the purposes of throw error messages with a context. rev2023.4.21.43403. If the function f was invoked by the top-level code, the value of f.caller is null; otherwise it's the function that called f. If the function that called f is a strict mode function, the value of f.caller is also null. It's a Primitive select. I already mentioned it. // First line inside a .js file 'use strict'; // rest of the script That's why you are getting error:MyFunction. Or will it be in future plans ECMA6, 7? All browser compatibility updates at a glance, Frequently asked questions about MDN Plus. Why in the Sierpiski Triangle is this set being used as the example for the OSC and not a more "natural"? Though some browsers might still support it, it may have already been removed from the relevant web standards, may be in the process of being dropped, or may only be kept for compatibility purposes. Not the answer you're looking for? "use strict"; Defines that Strict mode is declared by adding "use strict"; to the beginning of a Strict mode makes great strides toward treating eval and arguments as keywords. Why does awk -F work for most letters, but not for the letter "t"? How to get the function name under "use strict"? ES6 class methods. Is there any way, in javascript, to obtain the name of the function, inside the function which was called, javascript - Get name of function through a function, How to compare a function when the function is created as the result of another function. This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. In strict mode, this is a syntax error. In strict mode, the value is passed directly without conversion or replacement. For logging/debugging purposes, you can create a new Error object in the logger and inspect its .stack property, e.g. after: In strict mode, eval creates variables only for the code being evaluated, so eval can't affect whether a name refers to an outer variable or some local variable: Whether the string passed to eval() is evaluated in strict mode depends on how eval() is invoked (direct eval or indirect eval). Why not just write. How to get file input by selected file name without path using jQuery ? With the introduction of computed property names, making duplication possible at runtime, this restriction was removed in ES2015. Not the answer you're looking for? throw myFunctionName() + ': invalid number of arguments'; For now I have to hard-code the function name within the throws. var functionName = function() {} vs function functionName() {}. Adding EV Charger (100A) in secondary panel (100A) fed off main (200A). The fact that you want the function name is probably a good indication that you're thinking about the problem incorrectly. In strict mode code, eval doesn't create a new variable in the scope from which it was called. Why doesnt a Javascript return statement work when the return value is on a new line. As noted this applies only if your script uses "strict mode". One interesting way I'm experimenting with is a declaration like the following: It's a little hacky, but what ends up happening is test1 is a local variable that holds a [Function: test1] object. What is the scope of variables in JavaScript? The caller accessor property of Function instances returns the function that invoked this function. Why? Literature about the category of finitary monads. Avoid using it, and update existing code if possible; see the compatibility table at the bottom of this page to guide your decision. When adding 'use strict';, the following cases will throw a SyntaxError before the script is executing: These errors are good, because they reveal plain errors or bad practices. Can you still use Commanders Strike if the only attack available to forego is an attack against an ally? JavaScript in browsers can access the user's private information, so such JavaScript must be partially transformed before it is run, to censor access to forbidden functionality. Beginner kit improvement advice - which lens should I consider? The following code checks the value a function's caller property. In strict mode, a variable can not be used before it is declared: In strict mode, eval() can not declare a variable using the var keyword: eval() can not declare a variable using the let keyword: The this keyword in functions behaves Eliminates some JavaScript silent errors by changing them to throw errors. Careful review of your code base will probably be necessary to be sure these differences don't affect the semantics of your code. Table Of Contents duplicating parameter in regular JS function; duplicating parameter in non strict mode; duplicating parameter in strict mode; How do arrow functions treat duplicate parameters You can bind function as its context then you can access its name via this.nameproperty: After little research here is a good solution : Source : https://gist.github.com/dfkaye/6384439, Building on @georg solution, this one returns just the function name. Which one to choose? Note: Making code that used to error become non-errors is always considered backwards-compatible. Learn more about bidirectional Unicode characters. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. 565), Improving the copy in the close modal and post notices - 2023 edition, New blog post from our CEO Prashanth: Community is the future of AI. Confirmed working in Node v16.13.0. On whose turn does the fright from a terror dive end? Using the function.caller Property In this approach, we will use the function.caller property in JavaScript. Difference between var and let in JavaScript, Convert a string to an integer in JavaScript. In strict mode, a function declaration inside a block is only visible inside the block. Javascript Functions & Parameters | Javascript Tutorial For Beginners, 16.13: async/await Part 1 - Topics of JavaScript/ES8, Can I get the name of the currently running function in JavaScript - JavaScript. Strict mode treats these mistakes as errors so that they're discovered and promptly fixed. Making statements based on opinion; back them up with references or personal experience. To enable the strict mode place the directive 'use strict' at the top of a function body. You can use strict mode in all your programs. The guides area is designed to help developers learn to better interact with the date and time problem domain, and the Moment.js library. Which function is used to prevent code running before document loading in jQuery ? In sloppy mode, a number beginning with a 0, such as 0644, is interpreted as an octal number (0644 === 420), if all digits are smaller than 8. if(typeof ez_ad_units!='undefined'){ez_ad_units.push([[320,50],'errorsandanswers_com-box-3','ezslot_1',119,'0','0'])};__ez_fad_position('div-gpt-ad-errorsandanswers_com-box-3-0');I need the current function name as a string to log to our log facility. How to find inputs with an attribute name starting with specific letter or text using jQuery? In general you want to invoke strict mode because of its benefits to your code's reliability (see @JohnResig article). Was Stephen Hawking's explanation of Hawking Radiation in "A Brief History of Time" not entirely accurate? , so the answer from @Sayem is only valid if you aren't using strict mode. Actually, actually paying more attention to your question, it sounds like you might want the extra junk :), This worked for me but I think there's a typo in your regexp. Example 2: This example display currently running function using console.log method. Making statements based on opinion; back them up with references or personal experience. All browser compatibility updates at a glance, Frequently asked questions about MDN Plus. are not allow to access their receiver and function objects. You cannot deprecate/obsolete/kill that which is actively used all over the web. Strict mode reserves some more names than sloppy mode, some of which are already used in the language, and some of which are reserved for the future to make future syntax extensions easier to implement. How do you run JavaScript script through the Terminal? StackExchange.ready(function(){$.get("https://stackoverflow.com/posts/38435450/ivc/7a17");}); Read More how to monitor the network on node.js similar to chrome/firefox developer tools?Continue, Read More Call AngularJS from legacy codeContinue, Read More How can I add multiple sources to an HTML5 audio tag, programmatically?Continue, Read More webpack: Module not found: Error: Cant resolve (with relative path)Continue, Read More Why doesnt a Javascript return statement work when the return value is on a new line?Continue, Read More How to set time with date in momentjsContinue, The answers/resolutions are collected from stackoverflow, are licensed under. What was the actual cockpit layout and crew of the Mi-24A? This use case is weak: name the enclosing function! Trying to get f.[[Prototype]].caller", // caller is an own property with descriptor {value: null, writable: false, enumerable: false, configurable: false}, // f doesn't have an own property named caller. In strict mode, the arguments object is created and initialized with the same values than the named arguments, but changes to either the arguments object or the named arguments aren't reflected in one another. Strict mode makes arguments and eval less bizarrely magical. What differentiates living as mere roommates from living in a marriage-like relationship? Most current browsers support a name property on Function objects that was non-standard until ES2015, but no current version of IE does. To learn more, see our tips on writing great answers. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, @Nick: Oh, I know that JScript 5.5 does not implement Javascript 1.5. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. In function calls like f(), this value was the global object. "use strict"; var x = 1; // valid in strict mode y = 1; // invalid in strict mode. Trying to get f.[[Prototype]].caller, Checking the value of a function's caller property. Strict mode eliminates some JavaScript silent errors by changing them to throw errors. How do I get the current date in JavaScript? in strict mode): The syntax, for declaring strict mode, was designed to be compatible with How to flip an image on hover using CSS ? In strict mode, a TypeError is thrown. How to get currently running function name using JavaScript ? This is why W3C's attempts to deprecate tags like and has failed. You can enable strict mode in two different ways, globally and locally. How to call PHP function on the click of a Button ? const {stack} = obj; Tutorials, references, and examples are constantly reviewed to avoid errors, but we cannot warrant full correctness of all content. JavaScript used to silently fail in contexts where what was done should be an error. How to get the children of the $(this) selector? Connect and share knowledge within a single location that is structured and easy to search. There may also be large incompatibilities between implementations and the behavior may change in the future. Avoid using arguments.callee() by either giving function expressions a name or use a function declaration where a function must call itself. Strict mode has been designed so that the transition to it can be made gradually. How to get the ID of the clicked button using JavaScript/jQuery ? Using a variable, without declaring it, is not allowed: Using an object, without declaring it, is not allowed: Deleting a variable (or object) is not allowed. Strict mode makes several changes to normal JavaScript semantics: Strict mode applies to entire scripts or to individual functions. Assignments which would accidentally create global variables throw an error in strict mode: Strict mode makes assignments which would otherwise silently fail to throw an exception. Note that format of the string returned by Error.prototype.stack is implemented differently in different engines, so this probably won't work everywhere: About other solutions: arguments.callee is not allowed in strict mode and Function.prototype.calleris non-standard and not allowed in strict mode.