Improve usability of custom knobs- introduce nullability: nullable, n…

…oNullable, both

src/data/custom_knob.ts

@@ -1,9 +1,44 @@
 class CustomKnob {
   constructor(
     public type: string,
-    public nullable: boolean,
+    public nullabilitty: CustomKnobNullability,
     public value: string
   ) {}
+
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  static fromJson(json: any): CustomKnob {
+    const type = json.type;
+    const nullability = customKnobNullabilityFromString(json.nullability);
+    const value = json.value;
+    return new CustomKnob(type, nullability, value);
+  }
+
+  get nullable(): boolean {
+    return this.nullabilitty != CustomKnobNullability.nonNullable;
+  }
+
+  get nonNullable(): boolean {
+    return this.nullabilitty != CustomKnobNullability.nullable;
+  }
+}
+
+enum CustomKnobNullability {
+  nullable,
+  nonNullable,
+  both,
+}
+
+function customKnobNullabilityFromString(value: string): CustomKnobNullability {
+  switch (value) {
+    case "nullable":
+      return CustomKnobNullability.nullable;
+    case "nonNullable":
+      return CustomKnobNullability.nonNullable;
+    case "both":
+      return CustomKnobNullability.both;
+    default:
+      throw new Error(`Invalid CustomKnobNullability value: ${value}`);
+  }
 }
 
-export { CustomKnob };
+export { CustomKnob, CustomKnobNullability };

src/generators/file_content/base_generator.ts

@@ -23,12 +23,13 @@ abstract class BaseFileContentGenerator implements FileContentGenerator {
 
   private applyCustomKnobs() {
     for (const customKnob of this.customKnobs) {
-      if (customKnob.nullable) {
-        this.knobForNullableType.set(customKnob.type, (fieldName) =>
+      if (customKnob.nonNullable) {
+        this.knobForType.set(customKnob.type, (fieldName) =>
           customKnob.value.replace("$fieldName", fieldName)
         );
-      } else {
-        this.knobForType.set(customKnob.type, (fieldName) =>
+      }
+      if (customKnob.nullable) {
+        this.knobForNullableType.set(customKnob.type, (fieldName) =>
           customKnob.value.replace("$fieldName", fieldName)
         );
       }

src/global.d.ts

@@ -17,6 +17,8 @@ declare global {
 
   // eslint-disable-next-line @typescript-eslint/no-unused-vars
   interface Array<T> {
+    whereNotNull(): Array<T>;
+
     whereType<T>(): Array<T>;
   }
 }

src/providers/custom_knobs_provider.ts

@@ -10,9 +10,17 @@ class CustomKnobsProvider {
         vscode.Uri.file(filePath)
       );
       const fileContentString = Buffer.from(fileContent).toString("utf-8");
-      const parsedContent = JSON.parse(fileContentString) as Array<CustomKnob>;
-
-      return parsedContent;
+      const parsedContent = JSON.parse(fileContentString);
+      return parsedContent
+        .map((item: object) => {
+          try {
+            return CustomKnob.fromJson(item);
+          } catch (error) {
+            console.error("Error parsing custom knob:", error);
+            return null;
+          }
+        })
+        .whereNotNull();
     } catch (error) {
       console.error("Error reading JSON file:", error);
       return [];

src/util/extensions.ts

@@ -29,6 +29,10 @@ String.prototype.substringUpToAndIncluding = function (text: string) {
   return this.substring(0, this.indexOf(text) + text.length);
 };
 
+Array.prototype.whereNotNull = function <T>(): Array<T> {
+  return this.filter((item) => item !== null);
+};
+
 Array.prototype.whereType = function <T>(): Array<T> {
   return this.filter((element): element is T => !!element);
 };