Exporting

learn/store/queries/download.js

@@ -1,50 +1,108 @@
 (() => {
+    const saveRecords = (records, iteration, startTime) => {
+        return new Promise(
+            (resolve, reject) => {
+                const jsonStr = JSON.stringify(records);
+                console.log(`Iteration ${iteration}, saving ${records.length} records, taking ${jsonStr.length} characters, at ${(Date.now() - startTime)/1000}s`);
+
+                const blob = new Blob([jsonStr], { type: 'application/json;charset=utf-8;' });
+                const url = URL.createObjectURL(blob);
+                const el = document.createElement('a');
+                const d = new Date();
+
+                el.href = url;
+                el.download = `flist-profile-cache-${d.toISOString()}-${iteration}.json`;
+
+                document.body.appendChild(el);
+
+                el.click();
+
+                setTimeout(
+                    () => {
+                        document.body.removeChild(el);
+                        window.URL.revokeObjectURL(url);
+
+                        resolve();
+                    },
+                    0
+                );
+            }
+        );
+    }
+
+
+
     const conn = indexedDB.open('flist-ascending-profiles', 1);
 
     conn.onsuccess = (e) => {
         const db = e.target.result;
-        const txn = db.transaction('profiles', 'readonly');
-        const store = txn.objectStore('profiles');
-        const cursorReq = store.openCursor();
-        const records = [];
 
-        cursorReq.onsuccess = (ce) => {
-            const cursor = ce.target.result;
+        function getRecords(iteration, recordLimit, startTime) {
+            return new Promise(
+                (resolve, reject) => {
+                    const txn = db.transaction('profiles', 'readonly');
+                    const store = txn.objectStore('profiles');
 
-            if (!cursor) {
+                    const cursorReq = store.openCursor();
+                    const records = [];
+
+                    let hasAdvanced = false;
+
+                    cursorReq.onsuccess = (ce) => {
+                        const cursor = ce.target.result;
+
+                        if (!cursor) {
+                            if (records.length > 0) {
+                                saveRecords(records, iteration, startTime)
+                                    .then(() => resolve(false));
+                            }
+
+                            resolve(false);
+                            return;
+                        }
+
+                        if ((iteration > 0) && (hasAdvanced === false)) {
+                            console.log(`Advancing ${iteration * recordLimit} records`);
+                            hasAdvanced = true;
+                            cursor.advance(iteration * recordLimit);
+                            return;
+                        }
+
+                        records.push(cursor.value);
+
+                        if (records.length >= recordLimit) {
+                            saveRecords(records, iteration, startTime)
+                                .then(() => resolve(true));
+
+                            txn.abort();
+                            return;
+                        }
+
+                        cursor.continue();
+                    };
+                }
+            );
+        }
+
+        let iteration = 0;
+        const recordLimit = 2500;
+        const startTime = Date.now();
+
+        const getRecordsManager = async (shouldContinue) => {
+            if (!shouldContinue) {
+                console.log('Export Completed');
                 return;
             }
 
-            records.push(cursor.value);
-            cursor.continue();
-        };
+            iteration++;
 
-        txn.oncomplete = (te) => {
-            console.log('Found', records.length, 'records to download');
-            const blob = new Blob([JSON.stringify(records)], { type: 'application/json;charset=utf-8;' });
-            const url = URL.createObjectURL(blob);
-            const el = document.createElement('a');
-            const d = new Date();
+            const result = await getRecords(iteration, recordLimit, startTime);
 
-            el.href = url;
-            el.download = `flist-profile-cache-${d.toISOString()}.json`;
+            return getRecordsManager(result);
+        }
 
-            document.body.appendChild(el);
-
-            el.click();
-
-            setTimeout(
-                () => {
-                    document.body.removeChild(el);
-                    window.URL.revokeObjectURL(url);
-                },
-                0
-            );
-
-
-            // const a = records.length;
-            // debugger;
-        };
+        getRecords(iteration, recordLimit, startTime)
+            .then((shouldContinue) => getRecordsManager(shouldContinue));
     };
 })();