add more comments in the code

webserver/server/app/controllers/TransactionHistoryController.ts

@@ -98,26 +98,28 @@ export class TransactionHistoryController extends Controller {
 
       let pageStartWithSlot = pageStart;
 
+      // if the slotLimits field is set, this shrinks the tx id range
+      // accordingly if necessary.
       if (requestBody.slotLimits) {
         const bounds = slotBounds ? slotBounds[0] : { min_tx_id: -1, max_tx_id: -2 };
 
         const minTxId = Number(bounds.min_tx_id);
 
         if (!pageStartWithSlot) {
           pageStartWithSlot = {
+            // block_id is not really used by this query.
             block_id: -1,
+            // if no *after* argument is provided, this starts the pagination
+            // from the corresponding slot. This allows skipping slots you are
+            // not interested in. If there is also no slotLimits specified this
+            // starts from the first tx because of the default of -1.
             tx_id: minTxId,
           };
         } else {
-          if (minTxId > pageStartWithSlot.tx_id) {
-            pageStartWithSlot.tx_id = minTxId;
-          }
+          pageStartWithSlot.tx_id = Math.max(Number(bounds.min_tx_id), pageStartWithSlot.tx_id);
         }
 
-        const maxTxId = Number(bounds.max_tx_id);
-        if (maxTxId < until.tx_id) {
-          until.tx_id = maxTxId;
-        }
+        until.tx_id = Math.min(until.tx_id, Number(bounds.max_tx_id));
       }
 
       const commonRequest = {

webserver/shared/models/TransactionHistory.ts

@@ -1,6 +1,5 @@
 import type { Address } from "./Address";
 import type { BlockSubset } from "./BlockLatest";
-import { AssetName, PolicyId } from "./PolicyIdAssetMap";
 import type { Pagination, RelationFilter } from "./common";
 
 export type TransactionHistoryRequest = {
@@ -10,7 +9,11 @@ export type TransactionHistoryRequest = {
   /** Defaults to `ADDRESS_LIMIT.RESPONSE` */
   limit?: number;
 
+  /** This limits the transactions in the result to this range of slots.
+   * Everything else is filtered out */
   slotLimits?: SlotLimits;
+  /** If this is set to true, the result includes the input addresses (which are
+   * not part of the tx), and the metadata (if any) */
   withInputContext?: boolean;
 } & Pagination;
 
@@ -52,6 +55,8 @@ export type TransactionHistoryResponse = {
 };
 
 export type SlotLimits = {
+  // this is exclusive
   from: number;
+  // this is inclusive
   to: number;
 };