How to encapsulate methods in javascript

With the popularity of JavaScript and the expansion of its usage, more and more developers have discovered a problem with the code: too much repeated code. In order to solve this problem, many developers have begun to use a technology called "encapsulation method". This article will introduce how to encapsulate methods in JavaScript.

What is the encapsulation method?

The encapsulation method is a technique that encapsulates a piece of code into a single reusable function. This technique is sometimes called functional programming because it operates on code by defining and calling one or more functions.

Advantages:

1. Better readability and maintainability: By encapsulating the code in functions, we can use meaningful names in the code to describe the functionality , and this is what a good code should have. This approach makes the code easier to understand and maintain.
2. Lower maintenance costs: Because the code is encapsulated into a single function, it is easier to maintain. If we need to make changes to this functionality, we only need to change this function without changing the entire code base.
3. Higher reusability: When we need to perform the same or similar operations in different parts of the code base, we can call this function more easily instead of copying and pasting code snippets.

How to implement the encapsulation method?

In JavaScript, encapsulating methods is achieved by declaring a function. This function needs to accept some actual parameters, which are used inside the function. This function may or may not return a value.

The best practice for encapsulating methods is to encapsulate the code into a function and pass the data as a parameter to the function when calling the function. Functions can perform any logical AND operation on the data and return a result. The return value of a function can directly return a value, or it can return an object or array.

You can also encapsulate a module or object, which contains multiple related functions. This approach is more suitable for large applications or libraries.

Practical example of encapsulation

Let’s take a look at a simple example of JavaScript encapsulation method. Let's say we have some code that will set a cookie every time the page loads. This code can be written as a function like this:

function setCookie(name, value, days) {
    var expires = "";
    if (days) {
        var date = new Date();
        date.setTime(date.getTime() + (days * 24 * 60 * 60 * 1000));
        expires = "; expires=" + date.toGMTString();
    }
    document.cookie = name + "=" + value + expires + "; path=/";
}

Now, instead of copying and pasting this code snippet, we can call this function throughout our application to set cookies.

Here is another example, encapsulating a module:

var mathFunctions = {
  add: function (a, b) {
    return a + b;
  },
  subtract: function (a, b) {
    return a - b;
  },
  multiply: function (a, b) {
    return a * b;
  },
  divide: function (a, b) {
    return a / b;
  }
};

Using this method, we can call any function of this object through the module name. For example, we can execute mathFunctions.add(3, 5) and it will return 8.

Summary

In JavaScript, the encapsulation method is a technology that encapsulates code into functions. It offers several advantages, including better readability and maintainability, lower maintenance costs, and higher reusability. The best practice for implementing encapsulated methods is to encapsulate the code into a function or object and pass the data as a parameter to the function when it is called. This technique is especially useful in large applications and libraries.

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