All objects in JavaScript have a prototype. The prototype is another object that the original object inherits from, which is to say, the original object has access to all of its prototype’s methods and properties.

• All objects have a prototype
• The prototype is another object

Prototype Inheritance

1. We can define properties and functions common among all objects on the prototype to save memory. Defining every property and function takes up a lot of memory, especially if you have a lot of common properties and functions, and a lot of created objects! Defining them on a centralized, shared object which the objects have access to, thus saves memory.
2. The second reason is the name of this section, Prototypal Inheritance

Essentially, this is how JavaScript makes use of prototype 

• by having the objects contain a value
• to point to prototypes and inheriting from those prototypes, and thus forming a chain. This kind of inheritance using prototypes is hence named as Prototypal inheritance. JavaScript figures out which properties exist (or do not exist) on the object and starts traversing the chain to find the property or function.

Note:

1. Every prototype object inherits from Object.prototype by default.
2. An object’s Object.getPrototypeOf() value can only be one unique prototype object.