chore: document protoReflection.ts

src/common/utils/protoReflection.ts

@@ -1,26 +1,43 @@
 import * as pbjs from 'google-protobuf';
 
+// Protobuf Message itself
 type GenericObject<T extends pbjs.Message> = T;
+
+// Message's "setter" call
 type ProtoFunction<T extends pbjs.Message, U extends ReturnType<T['toObject']>> = (
     value: U[keyof U]
 ) => void;
 
+/**
+ * AsObjectToProto does the opposite of ProtoMessage.toObject().
+ * This function turns regular JS objects back into their source protobuf message type,
+ * with the help us copious amounts of reflection.
+ * @param protoClass A protobuf message class
+ * @param input A JS object that corresponds to the protobuf message class.
+ */
 export const AsObjectToProto = <T extends pbjs.Message>(
     protoClass: { new (): T },
     input: ReturnType<T['toObject']>
 ): GenericObject<T> => {
+    // First, we create the message itself
     const proto = new protoClass();
+
+    // We want the keys from the message, this will give us the setter names we need.
     const protoKeys = Object.getOwnPropertyNames((proto as any).__proto__);
 
+    // Loop over the input data keys
     for (let inputKey in input) {
+        // As we loop, find the setter function for the key
         const setCallName = protoKeys.find(
             (key) => `set${inputKey.toLowerCase()}` === key.toLowerCase()
         ) as keyof typeof proto;
 
+        // If we encounter a key without a place to go, we silently ignore it.
         if (!setCallName) {
             continue;
         }
 
+        // But, if it all succeeds, we call the setter with the JS object's value.
         ((proto[setCallName] as unknown) as ProtoFunction<T, typeof input>)(
             input[inputKey]
         );