this Keyword in Different Contexts

const obj = {
  value: 42,
  getValue() {
    return this.value;
  }
};

const getValue = obj.getValue;
console.log(getValue());

42
undefined
This demonstrates lost binding: 1) Method is assigned to a variable, losing its context, 2) Function is called without any context (default binding), 3) In non-strict mode, 'this' defaults to global object, 4) Global object doesn't have 'value' property, 5) Returns undefined instead of 42, 6) Common pitfall when working with methods as callbacks.
null
Reference Error