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• And JavaScript engines are highly optimized for this. Changing a prototype “on-the-fly” with Object.setPrototypeOf or obj.__proto__= is a very slow operation as it breaks internal optimizations for object property access operations.
• Object.getPrototypeOf(obj) – returns the [[Prototype]] of obj. Object.setPrototypeOf(obj, proto) – sets the [[Prototype]] of obj to proto.
• The only usage of __proto__, that’s not frowned upon, is as a property when creating a new object: { __proto__: ... }.
• Object.create(proto[, descriptors]) – creates an empty object with given proto as [[Prototype]] and optional property descriptors.
• The Object.create method is a bit more powerful, as it has an optional second argument: property descriptors.

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