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javascriptinheritanceconstructorprototype-programming

is Object.getPrototypeOf() same as Object.constructor.prototype in Javascript?

Is there a difference between Object.getPrototypeOf(obj) and obj.constructor.prototype? Or are these two referencing the same thing?

Solution

  • NO

    It returns the internal [[Prototype]] value.

    For example:

    var o = Object.create(null);
Object.getPrototypeOf(o); // null
o.constructor.prototype; // error

var p = {};
var o = Object.create(p);
Object.getPrototypeOf(o); // p
o.constructor.prototype; // Object.prototype

    o.constructor.prototype only works with objects created through new ConstructorFunction or where you have manually set the Prototype.prototype.constructor === Prototype relationship.