clean up and comment remFromList

1 files changed, 31 insertions, 18 deletions

diff --git a/src/server/websocket.ts b/src/server/websocket.ts
index 74b5dacaa..e94b48f4f 100644
--- a/src/server/websocket.ts
+++ b/src/server/websocket.ts
@@ -317,6 +317,18 @@ export namespace WebSocket {
         );
     }
 
+    /**
+     * findClosestIndex() is a helper function that will try to find
+     * the closest index of a list that has the same value as
+     * a specified argument/index pair. 
+     * @param list the list to search through
+     * @param indexesToDelete a list of indexes that are already marked for deletion
+     * so they will be ignored
+     * @param value the value of the item to remove
+     * @param hintIndex the index that the element was at on the client's copy of
+     * the data
+     * @returns the closest index with the same value or -1 if the element was not found.
+     */
     function findClosestIndex(list: any, indexesToDelete: number[], value: any, hintIndex : number) {
         let closestIndex = -1;
         for(let i = 0; i < list.length; i++) {
@@ -329,28 +341,31 @@ export namespace WebSocket {
         return closestIndex;
     }
 
+    /**
+     * remFromListField() receives the items to remove and a hint
+     * from the client, and attempts to make the modification to the 
+     * server's copy of the data. If server's copy does not match 
+     * the client's after removal, the server will SEND BACk
+     * its version to the client.
+     * @param socket the socket that the client is connected on
+     * @param diff an object containing the items to remove and a hint
+     * (the hint contains start index and deleteCount, the number of 
+     * items to delete)
+     * @param curListItems the server's current copy of the data
+     */
     function remFromListField(socket: Socket, diff: Diff, curListItems?: Transferable): void {
-        // console.log("##### %O", diff);
         diff.diff.$set = diff.diff.$remFromSet;
         delete diff.diff.$remFromSet;
-        // console.log(JSON.stringify(diff));
         const updatefield = Array.from(Object.keys(diff.diff.$set))[0];
-        // console.log("websocket/remfromlist: UPDATE FIELD: " + updatefield);
         const remListItems = diff.diff.$set[updatefield].fields;
         const curList = (curListItems as any)?.fields?.[updatefield.replace('fields.', '')]?.fields.filter((f: any) => f !== null) || [];
         const hint = diff.diff.$set.hint;
-        // console.log(remListItems);
-        // console.log(curList);
         
         
         if(hint) {
-            // console.log("websocket/remfromlist: %O", hint);
-            // console.log(findClosestIndex([5, 5, 3], [], 5, 0));
-            // console.log(findClosestIndex([5, 5, 3], [0], 5, 1));
+            // indexesToRemove stores the indexes that we mark for deletion, which is later used to filter the list (delete the elements)
             let indexesToRemove: number[] = [];
             for(let i = 0; i < hint.deleteCount; i++) {
-                // console.log("VALUE: %d", remListItems[i]);
-                // console.log("HINT INDEX: %d", i + hint.start);
                 if(curList[i + hint.start] == remListItems[i]) {
                     indexesToRemove.push(i + hint.start);
                     continue;
@@ -364,31 +379,29 @@ export namespace WebSocket {
                 }
             }
 
-            // console.log("INDEXES TO REMOVE: ", indexesToRemove);
             diff.diff.$set[updatefield].fields = curList?.filter(
                 (curItem: any, index : number) => !(indexesToRemove.includes(index))
             );
-            // console.log("websocket/remfromlist: newdiff: %O", diff.diff.$set[updatefield].fields);
         } else {
+            // go back to the original way to delete if we didn't receive
+            // a hint from the client
             diff.diff.$set[updatefield].fields = curList?.filter(
                 (curItem: any) => !remListItems.some((remItem: any) => (remItem.fieldId ? remItem.fieldId === curItem.fieldId :
                     remItem.heading ? remItem.heading === curItem.heading : remItem === curItem))
             );
-            // console.log("websocket/remfromlist: newdiff: %O", diff.diff.$set[updatefield].fields);
         }
 
-
+        // if the client and server have different versions of the data after
+        // deletion, they will have different lengths and the server will
+        // send its version of the data to the client
         const sendBack = diff.diff.length !== diff.diff.$set[updatefield].fields.length;
-        // console.log("websocket/remfromlist: DIFFY " + JSON.stringify(diff.diff.$set));
-        // console.log("websocket/remfromlist: DIFF LENGTH " + diff.diff.length);
-        // console.log("websocket/remfromlist: DIFF $SET " + diff.diff.$set[updatefield].fields);
         delete diff.diff.length;
         Database.Instance.update(
             diff.id,
             diff.diff,
             () => {
-                // console.log("websocket/remfromlist: lambda: %s", JSON.stringify(diff))
                 if (sendBack) {
+                    // the two copies are different, so the server sends its copy.
                     console.log('SEND BACK');
                     const id = socket.id;
                     socket.id = '';