feat: more compact rendering of empty arrays and objects (#27)

Author: trentm

CHANGELOG.md

@@ -1,5 +1,11 @@
 # ecslog changelog
 
+## Unreleased
+
+- Make rendering of empty arrays and objects in the extra fields more compact.
+  They are now rendered as "[]" and "{}" rather than "[\n]" and "{\n}".
+  ([#27](https://github.com/trentm/go-ecslog/pull/27))
+
 ## v0.5.0
 
 - Add a `-i, --include-fields FIELDS` flag for including only certain fields.

internal/ecslog/formatters.go

@@ -335,7 +335,7 @@ func formatJSONValue(b *strings.Builder, v *fastjson.Value, currIndent, indent s
 			formatJSONValue(b, subv, currIndent+indent, indent, painter, compact, nestedIncludeFields)
 			i++
 		})
-		if !compact {
+		if !compact && i != 0 {
 			b.WriteByte('\n')
 			b.WriteString(currIndent)
 		}
@@ -356,7 +356,7 @@ func formatJSONValue(b *strings.Builder, v *fastjson.Value, currIndent, indent s
 			}
 			formatJSONValue(b, subv, currIndent+indent, indent, painter, compact, includeFields)
 		}
-		if !compact {
+		if !compact && len(v.GetArray()) != 0 {
 			b.WriteByte('\n')
 			b.WriteString(currIndent)
 		}