Are the two defining methods pretty much the same? Is there anything I should watch out for?
// A.
function Dog(name, color, numLegs) {
this.name = name;
this.color = color;
this.numLegs = numLegs;
}
Dog.prototype.greet = function() {
return 'Bark!';
}
// B.
class Dog {
constructor(name = '', color = '', numLegs = 0) {
this.name = name;
this.color = color;
this.numLegs = numLegs;
}
greet() {
return 'Bark!';
}
}
I'm refactoring an old application and I'm wondering if it's safe to restructure all existing object functions from (A) to (B) as shown above.
A js class is a beautified way of writing your first bit of code. So yes these two syntaxes do exactly the same thing.
class in JavaScript is a syntactic sugar of constructor functions. When you work with functions, you are dealing with prototypes and prototypal inheritance, whereas in a class it's more of coupling these actions together within a blueprint, which again makes use of functions and prototypes under the hood. In the first case, the function greet is a prototype property of the function Dog, meaning the instance of Dog will be able to access the method greet, and the same applies to the second case as well. (Make sure to use the new keyword when instantiating objects in both cases).