A global method is essentially a function that is a member of the global object. This means you can call it from anywhere in your code without needing to specify an object or instance to call it on.
Understanding Global Methods
Think of the global object as a container that holds all the default things available in your programming environment. Global methods, like alert() in JavaScript or similar functions in other languages, are directly accessible because they are properties of this global container. The reference states "A global method is a method of the global object."
How Global Methods Work
- Direct Access: Unlike methods tied to specific objects, global methods are available from anywhere in your code. You don't have to write
object.method(); instead, you just writemethod(). - Scope: Since they belong to the global scope, they can be called without any qualifiers or object references.
- Global Object: Global methods are part of the global object, which is where default functionalities of a programming environment are defined.
Example (JavaScript)
In JavaScript, functions like parseInt(), parseFloat(), and isNaN() are all examples of global methods. You call them directly, like this:
let number = parseInt("123"); // Directly using the global method parseInt()Global vs. Object Methods
| Feature | Global Method | Object Method |
|---|---|---|
| Access | Direct access, no object needed | Requires an object instance |
| Scope | Global scope | Object scope |
| Definition | Member of the global object | Member of an object class/instance |
| Use case | Core functionalities, utility methods | Operating on specific objects' data |
| Example (JS) | parseInt(), alert() |
array.push(), string.length |
Global Variables
Global variables are closely related to global methods, as "a global variable is a member of a global object." This means a global variable also does not require an object name to be referenced, just like global methods.
Summary
In summary, a global method is a readily accessible function that resides within the global scope, allowing you to invoke it directly without specifying an object. It's an essential part of most programming languages, providing core functionalities and utility tools at your fingertips. As the reference explains, "To reference a global property, you do not need to use an object name," and this also applies to both global methods and global variables.
