Restrictions on property names that should be accessed through dot '.' notation

Question | May 29, 2017 | nextptr 

The properties of an object can be accessed through subscript operator (obj.['nameOfProperty']) or dot notation (obj.nameOfProperty). For example, the object numbers has a property named fortyOne that can be accessed through both subscript operator and dot notation:

var numbers = { fortyOne: 41 };

// Both print 41 below
console.log( numbers['fortyOne'] );
console.log( numbers.fortyOne );

The subscript or brackets operator has no restrictions on how the properties should be named. However, not all property names are valid for access through dot notation. Select all the property names that can be accessed through dot notation (check Explanations for details):