Fix date arithmetic and simplify macOS date commands

Co-authored-by: larsdecker <1968186+larsdecker@users.noreply.github.com>

Author: Copilot

README.md

@@ -133,9 +133,8 @@ const client = new PinTanClient({
 const accounts = await client.accounts();
 
 // Fetch last 30 days of transactions
-const startDate = new Date();
-startDate.setDate(startDate.getDate() - 30);
 const endDate = new Date();
+const startDate = new Date(endDate.getTime() - 30 * 24 * 60 * 60 * 1000);
 
 const statements = await client.statements(accounts[0], startDate, endDate);
 

packages/fints-cli/README.md

@@ -283,10 +283,10 @@ fints-lib fetch-transactions \
 START_DATE=$(date -d "last month" +%Y-%m-01)
 END_DATE=$(date -d "-1 day $(date +%Y-%m-01)" +%Y-%m-%d)
 
-# For macOS (BSD date), use:
-# START_DATE=$(date -v-1m +%Y-%m-01)
-# END_DATE=$(date -v1d -v-1m -v-1d +%Y-%m-%d)
-# Or install GNU coreutils (brew install coreutils) and use 'gdate'
+# For macOS (BSD date), install GNU coreutils and use 'gdate':
+# brew install coreutils
+# START_DATE=$(gdate -d "last month" +%Y-%m-01)
+# END_DATE=$(gdate -d "-1 day $(gdate +%Y-%m-01)" +%Y-%m-%d)
 
 # Fetch transactions
 fints-lib fetch-transactions \

packages/fints/README.md

@@ -232,8 +232,7 @@ const accounts = await client.accounts();
 
 // Get transactions from the last 30 days
 const endDate = new Date();
-const startDate = new Date();
-startDate.setDate(startDate.getDate() - 30);
+const startDate = new Date(endDate.getTime() - 30 * 24 * 60 * 60 * 1000);
 
 const statements = await client.statements(accounts[0], startDate, endDate);