Public Instance Field Static in JavaScript

In this article, we will learn about public instance field static in JavaScript. Public instance field static is a proposal for a new syntax that allows us to declare and initialize public static fields in a class. Public static fields are properties that belong to the class itself, not to the instances of the class. They can be accessed and modified by anyone, using the class name as a prefix.

Why Use Public Instance Field Static?

Public instance field static is useful for several reasons:

• It can provide a clear and concise way to declare and initialize public static fields, without using the constructor or assignment statements.
• It can make the class definition more self-documenting, by showing the available public static fields and their default values.
• It can avoid the common pitfall of forgetting to use this when accessing or assigning public static fields, as they are automatically bound to the class.

How to Define Public Instance Field Static?

We can define public instance field static in JavaScript classes using the static keyword, followed by the = operator, the property name, and an optional initial value. The property name can be any valid identifier, or a computed expression enclosed in brackets. The initial value can be any valid expression, or omitted to default to undefined.

The syntax of defining a public instance field static is as follows:

                      
class ClassName {

  // Define the public static field with an optional initial value

  static propertyName = initialValue;

  // Define the public static field with a computed name and an optional initial value

  static [computedName] = initialValue;

}

                      
                  

Here is an example of defining public instance field static for a color and a shape property in a Shape class:

                      
class Shape {

  // Define the public static field color with an initial value

  static color = "blue";

  // Define the public static field shape with a computed name and an initial value

  static [Math.random() > 0.5 ? "shape" : "form"] = "circle";

}

                      
                  

How to Use Public Instance Field Static?

We can use public instance field static in JavaScript classes by accessing or assigning them using the dot notation or the bracket notation, just like any other property. However, we need to use the class name as a prefix, not the instance name. For example, if we have a shape instance of the Shape class, we can use the color and the shape fields as follows:

                      
// Access the color field using the dot notation

console.log(Shape.color); // "blue"

// Assign a new value to the color field using the bracket notation

Shape["color"] = "red";

// Access the shape field using the bracket notation

console.log(Shape.shape); // "circle"

// Assign a new value to the shape field using the dot notation

Shape.shape = "square";

                      
                  

Both statements will access or assign the public static fields of the Shape class, not the shape instance. They will also affect all the instances of the class, as they share the same public static fields.

Conclusion

In this article, we have learned about public instance field static in JavaScript. Public instance field static is a proposal for a new syntax that allows us to declare and initialize public static fields in a class. Public static fields are properties that belong to the class itself, not to the instances of the class. They can be accessed and modified by anyone, using the class name as a prefix. Public instance field static can make our code more readable and consistent, and enhance the functionality of our classes.