feat: add method to remove references from a thing

Fixes #6

src/connectorClient.ts

@@ -14,6 +14,8 @@
  */
 import {asyncPool} from '@krlwlfrt/async-pool';
 import {
+  isThing,
+  SCAssociatedThingWithoutReferences,
   SCBulkResponse,
   SCBulkRoute,
   SCLicensePlate,
@@ -68,6 +70,76 @@ export class ConnectorClient extends Client {
     return v5(uid.toString(), SCNamespaces[namespaceId]);
   }
 
+  /**
+   * Remove fields from a thing that are references
+   *
+   * This effectively turns a thing into a thing without references, e.g. SCDish into SCDishWithoutReferences.
+   *
+   * @param thing Thing to remove references from
+   */
+  static removeReferences<THING extends SCThings>(thing: THING): SCAssociatedThingWithoutReferences<THING> {
+    const thingWithoutReferences: any = {
+      ...{},
+      ...thing,
+    };
+
+    // iterate over all properties
+    for (const key in thingWithoutReferences) {
+      /* istanbul ignore if  */
+      if (!thingWithoutReferences.hasOwnProperty(key)) {
+        continue;
+      }
+
+      const property = thingWithoutReferences[key];
+
+      // check if property itself is a thing
+      if (isThing(property)) {
+        // delete said property
+        delete thingWithoutReferences[key];
+        continue;
+      }
+
+      // check if property is an array
+      if (Array.isArray(property)) {
+        if (property.every(isThing)) {
+          // delete property if every item in it is a thing
+          delete thingWithoutReferences[key];
+        } else {
+          // check every item in array
+          for (const item of property) {
+            if (['boolean', 'number', 'string'].indexOf(typeof item) >= 0) {
+              // skip primitives
+              continue;
+            }
+
+            // check every property
+            for (const itemKey in item) {
+              /* istanbul ignore if  */
+              if (!item.hasOwnProperty(itemKey)) {
+                continue;
+              }
+
+              if (isThing(item[itemKey])) {
+                // delete properties that are things
+                delete item[itemKey];
+              }
+            }
+          }
+        }
+      } else if (typeof property === 'object') {
+        // iterate over all properties in nested objects
+        for (const nestedKey in property) {
+          if (isThing(property[nestedKey])) {
+            // delete properties that are things
+            delete property[nestedKey];
+          }
+        }
+      }
+    }
+
+    return thingWithoutReferences as SCAssociatedThingWithoutReferences<THING>;
+  }
+
   /**
    * Request a bulk transfer to the backend
    *