FUNCTION PROPERTIES AND METHODS

Functions are objects in ECMAScript and, as mentioned previously, therefore have properties and methods. Each function has two properties: length and prototype. The length property indicates the number of named arguments that the function expects, as in this example:

function sayName(name) {
 console.log(name);
}   
          
function sum(num1, num2) {
 return num1 + num2;
}
          
function sayHi() {
 console.log("hi");
}
          
console.log(sayName.length); // 1
console.log(sum.length);     // 2
console.log(sayHi.length);   // 0

This code defines three functions, each with a different number of named arguments. The sayName() function specifies one argument, so its length property is set to 1. Similarly, the sum() function specifies two arguments, so its length property is 2, and sayHi() has no named arguments, so its length is 0.

The prototype property is perhaps the most interesting part of the ECMAScript core. The prototype is the...