feat(SmartdataDoc): add custom unique indexes

ts/smartdata.classes.doc.ts

@@ -12,7 +12,7 @@ export type TDocCreation = 'db' | 'new' | 'mixed';
  */
 export function svDb() {
   return (target: SmartDataDbDoc<any>, key: string) => {
-    console.log('called sva');
+    console.log(`called svDb() on ${key}`);
     if (!target.saveableProperties) {
       target.saveableProperties = [];
     }
@@ -20,6 +20,27 @@ export function svDb() {
   };
 }
 
+/**
+ * unique index - decorator to mark a unique index
+ */
+export function unI() {
+  return (target: SmartDataDbDoc<any>, key: string) => {
+    console.log('called unI');
+
+    // mark the index as unique
+    if (!target.uniqueIndexes) {
+      target.uniqueIndexes = [];
+    }
+    target.uniqueIndexes.push(key);
+
+    // and also save it
+    if (!target.saveableProperties) {
+      target.saveableProperties = [];
+    }
+    target.saveableProperties.push(key);
+  };
+} 
+
 export class SmartDataDbDoc<T> {
   /**
    * the collection object an Doc belongs to
@@ -31,6 +52,11 @@ export class SmartDataDbDoc<T> {
    */
   creationStatus: TDocCreation = 'new';
 
+  /**
+   * unique indexes
+   */
+  uniqueIndexes: string[];
+
   /**
    * an array of saveable properties of a doc
    */