Boilerplate code

Let’s prepare some convenient helpers for the journey ahead. We know we will need writing/reading to/from files and that we will need to transform some arguments, passed as strings, into Go types. Let’s deal with the latter first since this is a very trivial task.

Converting string to enum values

We are going to create two functions: strToPhoneType and strToDepartment. They look similar since we are going to check the value of the string and derive an enum value from it. Let’s start with strToPhoneType.

We know that the PhoneType enum contains the values TYPE_HOME, TYPE_MOBILE, TYPE_WORK, and TYPE_UNSPECIFIED. TYPE_UNSPECIFIED is the default value of PhoneType since enums have 0 as their default value. Conveniently, Golang initializes variables with 0 values. Thus, we will simply check for the values of home, mobile, and work. If the string does not contain anything or a value that isn’t one of these, the phone type will be considered...