How do I access the Object.prototype method in the following logic?

Question

You can access it via Object.prototype:

Object.prototype.hasOwnProperty.call(obj, prop);

That should be safer, because

• Not all objects inherit from Object.prototype
• Even for objects which inherit from Object.prototype, the hasOwnProperty method could be shadowed by something else.

Of course, the code above assumes that

• The global Object has not been shadowed or redefined
• The native Object.prototype.hasOwnProperty has not been redefined
• No call own property has been added to Object.prototype.hasOwnProperty
• The native Function.prototype.call has not been redefined

If any of these does not hold, attempting to code in a safer way, you could have broken your code!

Another approach which does not need call would be

!!Object.getOwnPropertyDescriptor(obj, prop);

For your specific case, the following examples shall work:

if(Object.prototype.hasOwnProperty.call(entries, "key")) {
    //rest of the code
}

OR

if(Object.prototype.isPrototypeOf.call(entries, key)) {
    //rest of the code
}

OR

if({}.propertyIsEnumerable.call(entries, "key")) {
    //rest of the code
}

It seems like this would also work:

key in entries

since that will return a boolean on whether or not the key exists inside the object?