In the provided code with obj and set, what is the output for obj.hasOwnProperty('1')?

In the provided code with obj and set, what is the output for obj.hasOwnProperty('1')?

• A. false
• B. true
• C. false
• D. true

Answer: (C)

To determine the output of `obj.hasOwnProperty('1')`, it's essential to understand what `hasOwnProperty` does and how JavaScript handles object properties. The `hasOwnProperty` method checks if a given property exists directly on the object in question, rather than inheriting it from its prototype chain. In this scenario, the property being checked is the string '1'. If the object `obj` does not have a property named '1' defined explicitly on it, `hasOwnProperty` will return false. Notably, if the object has numeric properties, they are converted to strings when accessed, which means that a number property would be accessed as a string ('1'). If `obj` was created without defining a property `'1'` directly, the method would return false, since the object will not own that property. Considering various scenarios where this can happen, such as when properties are defined using integer indices or if the property has been added through the prototype, it can clarify why `hasOwnProperty('1')` yields a false result in the correct answer. Understanding this concept of property ownership in JavaScript objects is key to interpreting the output of the `hasOwnProperty` function accurately.

To determine the output of obj.hasOwnProperty('1'), it's essential to understand what hasOwnProperty does and how JavaScript handles object properties.

The hasOwnProperty method checks if a given property exists directly on the object in question, rather than inheriting it from its prototype chain. In this scenario, the property being checked is the string '1'.

If the object obj does not have a property named '1' defined explicitly on it, hasOwnProperty will return false. Notably, if the object has numeric properties, they are converted to strings when accessed, which means that a number property would be accessed as a string ('1').

If obj was created without defining a property '1' directly, the method would return false, since the object will not own that property.

Considering various scenarios where this can happen, such as when properties are defined using integer indices or if the property has been added through the prototype, it can clarify why hasOwnProperty('1') yields a false result in the correct answer.

Understanding this concept of property ownership in JavaScript objects is key to interpreting the output of the hasOwnProperty function accurately.