diff --git a/UI/BigComponents/LayerSelection.ts b/UI/BigComponents/LayerSelection.ts
index 11237fa329..900be93489 100644
--- a/UI/BigComponents/LayerSelection.ts
+++ b/UI/BigComponents/LayerSelection.ts
@@ -77,7 +77,7 @@ export default class LayerSelection extends Combine {
         }
 
         const downloadButton = new SubtleButton("./assets/svg/floppy.svg", "Download visible data as geojson")
-        downloadButton.onClick(() => exportAsGeoJson(State.state.featurePipeline)) // TODO: Define this
+        downloadButton.onClick(() => exportAsGeoJson(State.state.featurePipeline))
         checkboxes.push(downloadButton)
 
         super(checkboxes)
diff --git a/UI/GeoJsonExport.ts b/UI/GeoJsonExport.ts
index 68037eee3e..d3e5dc5d68 100644
--- a/UI/GeoJsonExport.ts
+++ b/UI/GeoJsonExport.ts
@@ -1,14 +1,25 @@
 import FeaturePipeline from "../Logic/FeatureSource/FeaturePipeline";
 import {Utils} from "../Utils";
 
-export function exportAsGeoJson(featurePipeline: FeaturePipeline, options?: { metadata?: boolean }) {
+/**
+ * Exports given featurePipeline as a geojson FeatureLists (downloads as a json)
+ * @param featurePipeline The FeaturePipeline you want to export
+ * @param options The options object
+ * @param options.metadata True if you want to include the MapComplete metadata, false otherwise
+ */
+export function exportAsGeoJson(featurePipeline: FeaturePipeline, options: { metadata?: boolean} = {}) {
     let defaults = {
-        metadata: false
+        metadata: false,
     }
     options = Utils.setDefaults(options, defaults);
+
     // Select all features, ignore the freshness and other data
     let featureList: JSON[] = featurePipeline ? featurePipeline.features.data.map((feature) => feature.feature) : ["I'm empty"];
 
+    /**
+     * Removes the metadata of MapComplete (all properties starting with an underscore)
+     * @param featureList JsonList containing features, output object
+     */
     function removeMetaData(featureList: JSON[]) {
         for (let i=0; i < featureList.length; i++) {
             let feature = featureList[i];
@@ -18,13 +29,9 @@ export function exportAsGeoJson(featurePipeline: FeaturePipeline, options?: { me
                 }
             }
         }
-        return featureList;
     }
 
-    // Remove the metadata of MapComplete (all properties starting with an underscore)
-    if (!options.metadata) {
-        removeMetaData(featureList);
-    }
+    if (!options.metadata) removeMetaData(featureList);
 
     let geojson = {type: "FeatureCollection", features: featureList}
 
diff --git a/Utils.ts b/Utils.ts
index 418f1d1111..683e7a8f94 100644
--- a/Utils.ts
+++ b/Utils.ts
@@ -449,11 +449,10 @@ export class Utils {
     }
 
     public static setDefaults(options, defaults){
-        let result = {};
-        for (let key of defaults){
-            result[key] = key in options ? options[key] : defaults[key];
+        for (let key in defaults){
+            if (!(key in options)) options[key] = defaults[key];
         }
-        return result;
+        return options;
     }
 }
 
diff --git a/tslint.json b/tslint.json
index 6a204a045b..85c7437ac6 100644
--- a/tslint.json
+++ b/tslint.json
@@ -1,5 +1,5 @@
 {
-    "defaultSeverity": "error",
+    "defaultSeverity": "warn",
     "extends": [
         "tslint:recommended",
         "tslint-no-circular-imports"