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.
<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.
<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
<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