JavaScript Prototypes
Introduction to JavaScript prototypes and their uses.
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Background
We know about JavaScript objects and their mutation. We have assigned properties from one object to another. The question still remains. Is there a neater way of having all properties of another object?
Introduction to prototypes
All JavaScript objects have the property prototype. They go under the property name __proto__. The prototype of each object is assigned during creation and is itself an object. Look at the following code.
let vehicle = { wheels : 4 }; // object assigned to variable named vehiclelet car = { seats : 5 }; // object assigned to variable named carlet driver = {} // empty object assigned to variable named driver// Print all objects and __proto__ property for each variableconsole.log(`vehicle:`, vehicle, vehicle.__proto__);console.log(`car:`, car, car.__proto__);console.log(`driver:`, driver, driver.__proto__);
In the code above, each object is assigned to the three variables: vehicle, car, and driver (lines 1 to 3). We also print the __proto__ property for each variable, which is otherwise hidden when printing an object including an empty object (driver). The __proto__ property for each object can be seen as an empty object because the properties of the prototype object are ...