JavaScript Function.length property
Function.length property of the function object in Javascript is used to return the number of parameters required by a function.
Syntax:
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function.length
Parameters: This method requires no parameters.
Return: Return type is number.
Few examples are given below for a better understanding of the method.
Example 1:
html
<!DOCTYPE html><html lang="en"><head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <title>Document</title></head><body> <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></body></html> |
Output:
Example 2:
When number of parameters is greater than one.
html
<!DOCTYPE html><html lang="en"><head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <title>Document</title></head><body> <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></body></html> |
Output:
Example 3:
When array of arguments is given
html
<!DOCTYPE html><html lang="en"><head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <title>Document</title></head><body> <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></body></html> |
Output:
