What is a prototype in JavaScript anyway?

Let us look at the mystery of __proto__, [[prototype]] & prototype

[PS] This article promotes a YouTube channel I am working on. More of a link to the video sort of.

Nearly all objects in JavaScript are instances of Object; a typical object inherits properties (including methods) from Object.prototype

[[prototype]] && __proto__

The __proto__ getter function exposes the value of the internal [[Prototype]] of an object. For objects created using an object literal, this value is Object.prototype

The __proto__ setter allows [[Prototype]] of an object to be mutated. The object must be extensible according to Object.isExtensible(): if it is not, a TypeError is thrown. The value provided must be an object or null. Providing any other value will do nothing.

The use of __proto__ is controversial and discouraged. It was never originally included in the ECMAScript language spec, but modern browsers implemented it anyway. Only recently was the __proto__ property standardized by the ECMAScript 2015 specification for compatibility with web browsers, so it will be supported into the future. It is deprecated in favor of Object.getPrototypeOf/Reflect.getPrototypeOf and Object.setPrototypeOf/Reflect.setPrototypeOf (though still, setting the [[Prototype]] of an object is a slow operation that should be avoided if performance is a concern).

The __proto__ property can also be used in an object's literal definition to set the object [[Prototype]] on creation, as an alternative to Object.create().

In this video, let us talk about & see what is a prototype? We will see what is __proto__, what is the hidden property [[prototype]] & what is a function prototype? Let us also understand what is prototype chain & how it helps in prototypal inheritance in JavaScript.