How do you fix this in setTimeout inside a method in JavaScript?

Lost this in callbacks, arrow methods on objects (lexical this), forgetting new, this in setTimeout/forEach inside methods, destructured methods (detached), and expecting arrows to have object this.

Use .bind(obj) to permanently bind this, or wrap the method call in an arrow function (() => obj.method()). Arrows inherit this lexically from the enclosing scope, so they preserve the correct binding.

Because an arrow function's this is the enclosing scope's this, not the object. So obj.greet = () => this.name gives undefined. Use regular functions for methods so this is the object.