I always thought that a prototype
had some magic around it, but it seems that a prototype is actually just an object attached to a function. As an example:
function someMethod() {};
function Person(name) {
Object.assign(this, {name});
}
Person.prototype.number = 4;
Person.prototype.letter = "a";
Person.prototype.method = someMethod;
let obj = {
number:4,
letter:'a',
method: someMethod
};
console.log(`\
${Object.entries(Person.prototype).toString()}
${Object.entries(obj).toString()}
${Object.entries(Person.prototype).toString() == Object.entries(obj).toString()}\
`);
Is that more or less a correct understanding of what the prototype is? Or does any other machinery go on behind the scenes that the obj
in the above example does not include?
CodePudding user response:
A .prototype
object is indeed just an ordinary object. It is used in prototype chains like any other object can be used in them.
The only "magic" behind implicitly created .prototype
objects on function
s is that they have a non-enumerable .constructor
property that points back to the function.
function Person() {}
let obj = {};
console.log(Object.hasOwn(obj, 'constructor'));
console.log(Object.hasOwn(Person.prototype, 'constructor'));