From f95fd09112e81eab42591a5aaff3568ab06e9441 Mon Sep 17 00:00:00 2001
From: Rainer Killinger <killinge@hrz.uni-frankfurt.de>
Date: Mon, 15 Jul 2019 10:06:56 +0200
Subject: [PATCH] feat: add function to remove undefined properties

---
 src/connector-client.ts       | 32 ++++++++++++++++++++++++++++++++
 test/connector-client.spec.ts | 21 +++++++++++++++++++++
 2 files changed, 53 insertions(+)

diff --git a/src/connector-client.ts b/src/connector-client.ts
index cc838359..ec6e3d9f 100644
--- a/src/connector-client.ts
+++ b/src/connector-client.ts
@@ -155,6 +155,38 @@ export class ConnectorClient extends Client {
     return thingWithoutReferences as SCAssociatedThingWithoutReferences<THING>;
   }
 
+  /**
+   * Recursively deletes all undefined properties from an object instance
+   *
+   * @param obj Object to delete undefined properties from
+   */
+  static removeUndefinedProperties(obj: object): void {
+    // return atomic data types and arrays (recursion anchor)
+    if (typeof obj !== 'object' || Array.isArray(obj)) {
+      return;
+    }
+
+    // check each key
+    for (const key in obj) {
+      /* istanbul ignore if */
+      if (!obj.hasOwnProperty(key)) {
+        continue;
+      }
+
+      const indexedObj = obj as { [k: string]: unknown; };
+
+      if (typeof indexedObj[key] === 'undefined') {
+        // delete undefined keyss
+        delete indexedObj[key];
+      } else {
+        // check recursive
+        ConnectorClient.removeUndefinedProperties(indexedObj[key] as object);
+      }
+    }
+
+    return;
+  }
+
   /**
    * Request a bulk transfer to the backend
    *
diff --git a/test/connector-client.spec.ts b/test/connector-client.spec.ts
index 4565e5bc..015f2771 100644
--- a/test/connector-client.spec.ts
+++ b/test/connector-client.spec.ts
@@ -361,6 +361,27 @@ export class ConnectorClientSpec {
     }
   }
 
+  @test
+  async removeUndefinedProperties() {
+    const objectWithUndefinedProperties = {value: 'foo',
+                                           novalue: undefined,
+                                           nested: {
+                                             value: 'foo',
+                                             novalue: undefined},
+                                            };
+    const objectWithoutUndefinedProperties = {value: 'foo',
+                                              nested: {
+                                                value: 'foo'},
+                                               };
+    ConnectorClient.removeUndefinedProperties(objectWithUndefinedProperties);
+
+    expect(objectWithUndefinedProperties).to.deep.equal(objectWithoutUndefinedProperties, JSON.stringify(
+      [objectWithUndefinedProperties, objectWithoutUndefinedProperties],
+      null,
+      2,
+    ));
+  }
+
   @test
   async update() {
     const message: SCMessage = {