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Can JavaScript classes/objects have constructors? How are they created?
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Object Types (Blueprints) (Classes) They only create single objects. Sometimes we need a "blueprint" for creating many objects of the same "type". The way to create an "object type", is to use an object constructor function. In the example above, function Person() is an object constructor function.
In JavaScript, a constructor function is used to create objects. For example, // constructor function function Person () { this.name = 'John', this.age = 23 } // create an object const person = new Person(); Run Code. In the above example, function Person() is an object constructor function.
The constructor() method is a special method for creating and initializing objects created within a class.
A constructor is a function that creates and initializes an object. JavaScript provides a special constructor function called Object() to build the object. The return value of the Object() constructor is assigned to a variable. The variable contains a reference to the new object.
Using prototypes:
function Box(color) // Constructor { this.color = color; } Box.prototype.getColor = function() { return this.color; }; Hiding "color" (somewhat resembles a private member variable):
function Box(col) { var color = col; this.getColor = function() { return color; }; } Usage:
var blueBox = new Box("blue"); alert(blueBox.getColor()); // will alert blue var greenBox = new Box("green"); alert(greenBox.getColor()); // will alert green If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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