Assigning null to JSON fields instead of empty strings

Question

Since empty string is the zero/default value for Go string, I decided to define all such fields as interface{} instead. for example

Answer 1

For the case of a json object with null strings, its easiest to use the omitempty decorator on the field.

type student struct {
  FirstName  string `json:"first_name,omitempty"`
  MiddleName string `json:"middle_name,omitempty"`
  LastName   string `json:"last_name"`
}

With the above declaration, only if first_name was assigned will that key show up in the resultant json. last_name, on the otherhand, will always show up in the result with a value of "" if not assigned.

Now when you start including numeric fields where 0 could be a value, using omitempty doesn't do what one would expect. A 0 value always drops the field, and we need to be able to differentiate between a 0 value and an unassigned value. Here use of library such as https://github.com/guregu/null may be advisable.

More discussion here: https://www.sohamkamani.com/blog/golang/2018-07-19-golang-omitempty/