Object.create() vs. new SomeFunction(): When to Use Which JavaScript Inheritance Technique?

Object.create() vs new SomeFunction(): Demystifying Inheritance Techniques

The realm of object-oriented programming offers a variety of mechanisms to create and inherit objects. Two notable techniques in JavaScript are Object.create() and new SomeFunction(). While these constructs share similarities, they possess distinct characteristics and use cases.

Essential Differences

• Prototypical Inheritance: Object.create() establishes a direct prototypal relationship, where the specified object becomes the prototype of the new object. On the other hand, new SomeFunction() utilizes constructor functions to create objects, and by default, the function's prototype (not the function itself) serves as the prototype of the new object.
• Closures Accessibility: Due to JavaScript's lexical scoping, closures defined within the function body of new SomeFunction() are accessible via the new object's instance. In contrast, Object.create() does not support closure inheritance.

Why Use One Over the Other?

Use Object.create() when:

• You desire explicit prototypal inheritance, such as when creating lightweight helper objects or modifying existing prototypes dynamically.
• Closures are not essential for the created objects.

Use new SomeFunction() when:

• You require custom initialization logic or closure inheritance.
• You want to conform to standard object construction patterns.

Example Comparison

Consider the following code:

var test = {
  val: 1,
  func: function() {
    return this.val;
  }
};
var testA = Object.create(test);

var otherTest = function() {
  this.val = 1;
  this.func = function() {
    return this.val;
  };
};

var otherTestA = new otherTest();

Both testA and otherTestA inherit from the test and otherTest objects, respectively. However, testA maintains a direct prototypal relationship, while otherTestA initializes its properties within the constructor function.

By understanding these fundamental differences and use cases, you can effectively leverage Object.create() and new SomeFunction() to create suitable objects for your specific programming needs.

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