According to the ES2015 grammar, a property on an object literal can only be one of four things:

PropertyDefinition :

  • IdentifierReference
  • PropertyName : AssignmentExpression
  • MethodDefinition

The only one of these type that allows a leading get is MethodDefinition:

MethodDefinition :

  • PropertyName ( StrictFormalParameters ) { FunctionBody }
  • GeneratorMethod
  • get PropertyName ( ) { FunctionBody }
  • set PropertyName ( PropertySetParameterList ) { FunctionBody }

As you can see, the get form follows a very limited grammar that must be of the form

get NAME () { BODY }

The grammar does not allow functions of the form get NAME = ....