generate empty workbook if no data to add

README.md

@@ -22,6 +22,6 @@ Advanced settings can be provided via a top level json key named "config". Here
 
 | Key     | Example Value | Description               |
 |---------------|---------------|---------------------------|
-| key-order | "Column3,Column1,Column2"| Comma separated list of column names in the desired order |
-| overwrite-file | true | Boolean indicating whether output file should be overwritten if it already exists |
-| parent-node | "results" | Specify an alternate starting key for the spreadsheet data than just the first non-config key. Useful with json structures with multiple top-level keys |
+| keyOrder | "Column3,Column1,Column2"| Comma separated list of column names in the desired order |
+| overwriteFile | true | Boolean indicating whether output file should be overwritten if it already exists |
+| parentNode | "results" | Specify an alternate starting key for the spreadsheet data than just the first non-config key. Useful with json structures with multiple top-level keys |

cmd/main/main.go

@@ -114,18 +114,18 @@ func main() {
 
 		// Parse each key into our config struct
 		for _, key := range configKeys {
-			if strings.EqualFold(key, "key-order") {
-				fmt.Printf("Found config element for key-order\n")
+			if strings.EqualFold(key, "keyOrder") {
+				fmt.Printf("Found config element for keyOrder\n")
 				e, _ := configMap.Get(key)
 				for i, e := range strings.Split(e.(string), ",") {
 					config.keyOrder[i] = e
 				}
 				fmt.Printf("Column order is now : '%v'\n", config.keyOrder)
-			} else if strings.EqualFold(key, "overwrite-file") {
+			} else if strings.EqualFold(key, "overwriteFile") {
 				fmt.Printf("Found config element for overwriting output file\n")
 				e, _ := configMap.Get(key)
 				overwriteFile = e.(bool)
-			} else if strings.EqualFold(key, "parent-node") {
+			} else if strings.EqualFold(key, "parentNode") {
 				fmt.Printf("Found config element for forcing parent key for spreadsheet data\n")
 				e, _ := configMap.Get(key)
 				config.parentOverride = e.(string)
@@ -153,6 +153,16 @@ func main() {
 	// Get an interface that we can work with to access the sub elements
 	vslice := vislice.([]interface{})
 
+	if len(vslice) < 1 {
+		// There was no data but lets just log that and close off the empty workbook
+		fmt.Printf("No data found contained in top-level json key '%s', no work to do.\n", parentNode)
+		// Close off the file
+		if err := xlsx.SaveAs(outputFilename); err != nil {
+			log.Fatal(err)
+		}
+		return
+	}
+
 	// Check that the first element is what we expected
 	if _, ok := vslice[0].(orderedmap.OrderedMap); !ok {
 		error := fmt.Sprintf("Type of first vslice element is not an ordered map. It appears to be '%v'\n", reflect.TypeOf(vslice[0]))