The Javascript Function.length property of the function object in Javascript is used to return the number of parameters required by a function.
Syntax:
function.length
Parameters: This method requires no parameters.
Return: Return type is number.
A few examples are given below for a better understanding of the method.
Example 1: When the number of parameters is zero.
Javascript
<script>     // Creating function name func     // When no parameters are given     function func1(){}     console.log(     "The number of parameters required by "+      "the function are: ", func1.length) </script> |
Output:
The number of parameters required by the function are: 0
Example 2: When the number of parameters is greater than one.
Javascript
<script>     // Creating function name func     // When one parameters are given     function func1(a){}     console.log(     "The number of parameters required by the func1 are: ",       func1.length)     // When two parameters are given     function func2(a, b){}     console.log(     "The number of parameters required by the func2 are: ",      func2.length)     // When three parameters are given     function func3(a, b, c){}     console.log(     "The number of parameters required by the func3 are: ",      func3.length)     // When four parameters are given     function func4(a, b, c, d){}     console.log(     "The number of parameters required by the func4 are: ",      func4.length) </script> |
Output:
The number of parameters required by the func1 are: 1 The number of parameters required by the func2 are: 2 The number of parameters required by the func3 are: 3 The number of parameters required by the func4 are: 4
Example 3: When an array of arguments is given
Javascript
<script>     // Creating function name func     // When array of arguments are given     function func4(...args){}     console.log(     "The number of parameters required by the func4 are: ",      func4.length) </script> |
Output:
The number of parameters required by the func4 are: 0
We have a complete list of Javascript Function methods, to check those please go through this Javascript Function Complete reference article.
Supported Browser:
- Chrome 1 and above
- Edge 12 and above
- Firefox 1 and above
- Internet Explorer 4 and above
- Opera 3 and above
- Safari 1 and above
