Issue with observable fork join - sqlite

Question

Hi I have 3 tables of which, each one is child of another. I wrote a method to fetch from sqllite db as follows
public downloadFromOfflineDB(db,testSO){
var observableBatch = [];
observableBatch.push(db.executeSql("select * from TMP_AUD WHERE CRE_BY=? AND AUD_NUMBER=? ",
[localStorage.getItem("user_name"), testSO.auditNumber]).then(
response => {
this._util.logData('In downloadPendingInstancesForSyncFromOfflineDB- folder'+response.rows.length+'ID= '+response.rows.item(0).FLD_NUMBER);
if (response && response.rows && response.rows.length > 0) {
if (response && response.rows && response.rows.length > 0) {
var FLD_NUMBER = response.rows.item(0).FLD_NUMBER;
var folderArray = []
observableBatch.push(db.executeSql("select * from TMP_FOLDER WHERE CRE_BY=? AND FLD_NUMBER=? ",
[localStorage.getItem("user_name"), FLD_NUMBER]).then(
a => {
this._util.logData('In downloadPendingInstancesForSyncFromOfflineDB-TMP_FOLDER'+a.rows.length);
if (a && a.rows && a.rows.length > 0) {
for (let i = 0; i < a.rows.length; i++) {
var folderObj = {
folderName: a.rows.item(i).FLD_NAME,
files:[]
}
var FLD_NAME = a.rows.item(i).FLD_NAME
this._util.logData('In downloadPendingInstancesForSyncFromOfflineDB-TMP_FOLDER '+FLD_NAME);
observableBatch.push( db.executeSql("select * from TMP_FILES WHERE CRE_BY=? AND FLD_NAME=? ",
[localStorage.getItem("user_name"), FLD_NAME]).then(
b => {
this._util.logData('In downloadPendingInstancesForSyncFromOfflineDB-TMP_FILES'+b.rows.length);
var fileArray = [];
if (b && b.rows && b.rows.length > 0) {
for (let j = 0; j < b.rows.length; j++) {
var fileSO = {
compliance: b.rows.item(j).COMPLIANCE,
remarks: b.rows.item(j).REMARKS,
fileName: b.rows.item(j).FILE_NAME,
title: b.rows.item(j).TITLE
}
);
fileArray.push(fileSO);
}}
folderObj.files=fileArray;
}).catch(
e => {
this._util.logData('For sync error'+JSON.stringify(e));
return Observable.throw("An error occurred during sync");
})
);
folderArray.push(folderObj);
}}
}).catch(
e => {
this._util.logData('For sync error'+JSON.stringify(e));
return Observable.throw("An error occurred during sync");
})
);
}
}
testSO.folderArray = folderArray;
this._util.logData('Candidate for selected for sync' + JSON.stringify(testSO));
})
);
return Observable.forkJoin(observableBatch);
}
The issue here is below method is not waiting for all the calls to finish
public getFiles(testSO) {
return Observable.create(observer => {
this.platform.ready().then(() => {
this.sqlite.create({
name: 'offline.db',
location: 'default'
}).then((db: SQLiteObject) => {
this.downloadFromOfflineDB(db, testSO).subscribe(c => {
observer.next(c[0]);//This is undefined
observer.complete();
},
error => {
observer.error("An error occurred sync files.");
});
});
});
});
}
First method is executing, while second method returns before first execution is complete and I am not getting my object testSO populated. Can someone please guide me and tel me what I am doing wrong here.I used observable fork Join.

Answer 1

Looks like you are calling Observable.forkJoin(observableBatch) with only one item - result of db.executeSql. When you add more items later on it doesn't affect forkJoin.