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697What is a Prototype?
698The Prototype Chain Concept
699Object.getPrototypeOf()
700The __proto__ Accessor
701Prototypes vs Own Properties
702hasOwnProperty() Method
703The End of the Chain: null
704Property Lookup Performance
705Shadowing Properties
706Enumeration and the Prototype Chain
707Object.prototype Methods
708Changing an Object's Prototype
709Visualizing the Prototype Chain
710Common Prototype Chain Pitfalls
711The Two Different 'prototype' Concepts
712The 'prototype' Property on Functions
713The [[Prototype]] Internal Slot
714Accessing [[Prototype]] with __proto__
715How 'new' Connects prototype to __proto__
716Constructor Functions and Their prototype Property
717Instance __proto__ Points to Constructor.prototype
718The prototype.constructor Back-Reference
719Why __proto__ Is Deprecated in Modern Code
720Common Mistakes: Confusing the Two
721Visualizing the prototype vs __proto__ Relationship
722What Object.create Does
723Object.create(null) for Property Maps
724Setting Up Prototype Chains Manually
725The propertiesObject Parameter
726Object.create vs Constructor Functions
727Implementing Inheritance with Object.create
728Avoiding Constructor Pitfalls
729Mixins with Object.create
730Performance Considerations
731When Object.create Is the Right Tool
732What the 'new' Operator Does
733Constructor Functions vs Regular Functions
734The Implicit Return with 'new'
735Prototype Property of Constructor Functions
736The Constructor Property
737What instanceof Checks
738Using instanceof with Built-in Types
739instanceof Across Realms and Frames
740Forgetting 'new': The Pitfall
741Guarding Against Missing 'new'
742Manually Simulating 'new'
743When to Use 'new' vs Class Syntax

697What is a Prototype?
698The Prototype Chain Concept
699Object.getPrototypeOf()
700The __proto__ Accessor
701Prototypes vs Own Properties
702hasOwnProperty() Method
703The End of the Chain: null
704Property Lookup Performance
705Shadowing Properties
706Enumeration and the Prototype Chain
707Object.prototype Methods
708Changing an Object's Prototype
709Visualizing the Prototype Chain
710Common Prototype Chain Pitfalls
711The Two Different 'prototype' Concepts
712The 'prototype' Property on Functions
713The [[Prototype]] Internal Slot
714Accessing [[Prototype]] with __proto__
715How 'new' Connects prototype to __proto__
716Constructor Functions and Their prototype Property
717Instance __proto__ Points to Constructor.prototype
718The prototype.constructor Back-Reference
719Why __proto__ Is Deprecated in Modern Code
720Common Mistakes: Confusing the Two
721Visualizing the prototype vs __proto__ Relationship
722What Object.create Does
723Object.create(null) for Property Maps
724Setting Up Prototype Chains Manually
725The propertiesObject Parameter
726Object.create vs Constructor Functions
727Implementing Inheritance with Object.create
728Avoiding Constructor Pitfalls
729Mixins with Object.create
730Performance Considerations
731When Object.create Is the Right Tool
732What the 'new' Operator Does
733Constructor Functions vs Regular Functions
734The Implicit Return with 'new'
735Prototype Property of Constructor Functions
736The Constructor Property
737What instanceof Checks
738Using instanceof with Built-in Types
739instanceof Across Realms and Frames
740Forgetting 'new': The Pitfall
741Guarding Against Missing 'new'
742Manually Simulating 'new'
743When to Use 'new' vs Class Syntax

Lesson 739 of 2,723·17. Prototypes and InheritancePro lesson

instanceof Across Realms and Frames

Learn why instanceof can fail when objects come from different execution contexts or iframes.

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