(feat) add argument --null-as-default-value to use null as default value for extracted translations

src/post-processors/null-as-default-value.post-processor.ts

@@ -0,0 +1,12 @@
+import { TranslationCollection } from '../utils/translation.collection';
+import { PostProcessorInterface } from './post-processor.interface';
+
+export class NullAsDefaultValuePostProcessor implements PostProcessorInterface {
+
+	public name: string = 'NullAsDefaultValue';
+
+	public process(draft: TranslationCollection, extracted: TranslationCollection, existing: TranslationCollection): TranslationCollection {
+		return draft.map((key, val) => existing.get(key) === undefined ? null : val);
+	}
+
+}