Continue List.Generate() even when API request is Null to Allow for Incremental Refresh

artemus Thank you for your reply. I did attempt to try the List.Select as a wrapper around the List.Generate call and while doing so, I stumbled upon the realization that List.Generate wasn't just stopping when it received back an empty list. The problem wound up being that I had the code set to both add 100 to the offset and also add a day on each loop. This resulted in each day that was queried to already have an offset other than 0 and so after a few days passed, the offset was so high that the query to the api always returned an empty set. To fix the issue, I adjusted my code to account for this. See below. Thank you again for your help. 

Function

(Offset as number, endpoint as text, ext as text, eventDate as datetime)=>
let
    token_url = tokenUrl,    
    body = "Client_id="&clientKey&"&Client_secret="&clientSecret&"&Grant_type="&grantType,
    Source = Json.Document(Web.Contents(token_url,
    [
        Headers = [#"Content-Type"="application/x-www-form-urlencoded"],
        Content = Text.ToBinary(body)
    ]
    )
    ),
    token = Source[access_token],
    data = Json.Document(Web.Contents("https://edfiapi.nefec.org/v5.2.0/DS/api",
    [
        Headers = [#"Authorization"="Bearer "&token,#"Content-Type"="application/json"],
        RelativePath="/data/v3/"&ext&"/"&endpoint,
        Query = [#"limit"="100",#"offset"=Number.ToText(Offset),#"eventDate"=Text.Replace(Date.ToText(DateTime.Date(eventDate)), "/","-")]
    ]
    )
    )
    ,#"Data" = data
in
    #"Data"

Table

let
    Source = List.Generate(()=> [Result = fApiDate(0,endpoint,ext,eventDate), offset=0, endpoint="studentSectionAttendanceEvents", ext="ed-fi", eventDate=RangeStart],
                                each [eventDate] <= RangeEnd,
                                each if 
                                        List.IsEmpty([Result]) then
                                            [Result = fApiDate([offset], [endpoint], [ext], [eventDate]), offset = 0, endpoint=[endpoint], ext=[ext], eventDate=Date.AddDays([eventDate], 1)]
                                            else [Result = fApiDate([offset], [endpoint], [ext], [eventDate]), offset = [offset]+100, endpoint=[endpoint], ext=[ext], eventDate=[eventDate]] ,
                                each [Result]
                
    ),
    #"Converted to Table" = Table.FromList(Source, Splitter.SplitByNothing(), null, null, ExtraValues.Error),
    #"Expanded Column1" = Table.ExpandListColumn(#"Converted to Table", "Column1"),
    #"Expanded Column2" = Table.ExpandRecordColumn(#"Expanded Column1", "Column1", {"id", "sectionReference", "studentReference", "attendanceEventCategoryDescriptor", "eventDate", "_etag"}, {"id", "sectionReference", "studentReference", "attendanceEventCategoryDescriptor", "eventDate", "_etag"}),
    #"Expanded sectionReference" = Table.ExpandRecordColumn(#"Expanded Column2", "sectionReference", {"localCourseCode", "schoolId", "schoolYear", "sectionIdentifier", "sessionName"}, {"localCourseCode", "schoolId", "schoolYear", "sectionIdentifier", "sessionName"}),
    #"Expanded studentReference" = Table.ExpandRecordColumn(#"Expanded sectionReference", "studentReference", {"studentUniqueId"}, {"studentUniqueId"}),
    #"Removed Blank Rows" = Table.SelectRows(#"Expanded studentReference", each not List.IsEmpty(List.RemoveMatchingItems(Record.FieldValues(_), {"", null}))),
    #"Removed Duplicates" = Table.Distinct(#"Removed Blank Rows"),
    #"Changed Type" = Table.TransformColumnTypes(#"Removed Duplicates",{{"id", type text}, {"localCourseCode", type text}, {"schoolId", Int64.Type}, {"schoolYear", Int64.Type}, {"sectionIdentifier", type text}, {"sessionName", type text}, {"studentUniqueId", type text}, {"attendanceEventCategoryDescriptor", type text}, {"eventDate", type datetime}, {"_etag", Int64.Type}}),
    #"Filtered Rows" = Table.SelectRows(#"Changed Type", each [eventDate] >= RangeStart and [eventDate] <= RangeEnd)
in
    #"Filtered Rows"