Checks how many arguments a function takes in Javascript?

by

Function.length will do the job (really weird, in my opinion)

function test( a, b, c ){}

alert( test.length ); // 3

By the way, this length property is quite useful, take a look at these slides of John Resig’s tutorial on Javascript

EDIT

This method will only work if you have no default value set for the arguments.

function foo(a, b, c){};
console.log(foo.length); // 3


function bar(a="", b = 0, c = false){};
console.log(bar.length); // 0

The .length property will give you the count of arguments that require to be set, not the count of arguments a function has.

More Related Contents:

  1. CSS or jQuery : How to get visible top [duplicate]
  2. Get this error: “Uncaught TypeError: Cannot read property ‘0’ of undefined”
  3. setState doesn’t update the state immediately
  4. How to convert decimal to hexadecimal in JavaScript
  5. Understanding the difference between Object.create() and new SomeFunction()
  6. How do I fix CLIENT_MISSING_INTENTS error?
  7. How to check if object property exists with a variable holding the property name?
  8. How to check if a variable is an integer in JavaScript?
  9. How to replace all dots in a string using JavaScript
  10. Function in JavaScript that can be called only once
  11. How to prevent Unicode characters from rendering as emoji in HTML from JavaScript?
  12. Chrome, Javascript, window.open in new tab
  13. Can I run javascript before the whole page is loaded?
  14. How to turn NaN from parseInt into 0 for an empty string?
  15. How do I clear the content of a div using JavaScript? [closed]
  16. What is #auto attribute here and why it is required
  17. Access my entire browsing history via Javascript
  18. Can I use arrow function in constructor of a react component?
  19. javascript – remove array element on condition
  20. Javascript Code works in jsfiddle and but not in the Browser [closed]
  21. Node.js: SyntaxError: Cannot use import statement outside a module
  22. jQuery() not finding elements in jQuery.parseHTML() result
  23. How can I disable all typescript type checking?
  24. Maximum item size in IndexedDB
  25. Responding to the onmousemove event outside of the browser window in IE
  26. React hook useEffect runs continuously forever/infinite loop
  27. MissingSchemaError: Schema hasn’t been registered for model “User”
  28. simplest cross-browser check if protocol handler is registered
  29. Delay script loading
  30. JavaScript Namespace Declaration

Leave a Comment