pouchdb: [bug] WebSQL adapter not detected correctly in pouchdb-adapter-websql/src/valid.js (when SQLite Plugin 2 + Cordova used)

Environment

Hybrid App

• cordova 6.2.0
• cordova-plugin-wkwebview-engine
• cordova-labs-local-webserver
• cordova-plugin-sqlite-2

Browser/platform

iOS 9.3.2 WKWebView via cordova plugin

Adapter

WebSQL - via cordova-plugin-sqlite-2

Server CouchDB

CouchDB

Please describe your issue.

I have a hybrid app running successfully on iOS 9.3.2 using the faster WKWebView and PouchDB 5.3.2 ( {adapter: 'websql'} and cordova-plugin-sqlite-2. All good.

If I change nothing else but bump my package.json pouchdb version to 5.4.x and then npm install and build/run my app on my device I get the error: Error: Adapter is missing

I had to dig for the error using Safari Dev tools and found it in the taskqueue of my local db object. i.e.

var db = new PouchDB('mydb', {adapter: 'websql', revs_limit: 100, auto_compaction: true});
console.log(db);    // db.taskqueue.failed : 'Error: Adapter is missing'

If I swap back to 5.3.2, all is good and app works perfectly.

I noticed there were some deprecations in 5.4.0 but not sure if these are to blame. I’m more suspicious of bugfix #5197 / PR #5198. I get why this fix was introduced for browser validation, but with cordova + sqlite plugin 2 we can get it to work. Are we artificially disabling websql here for cordova apps too ?

Edit: Turns out we are: valid.js#L56 assumes a SQLitePlugin object is defined before deviceready.

But with cordova-plugin-sqlite-2 the object isn’t available until the deviceready event fires and it is different casing sqlitePlugin i.e. there is no SQLitePlugin object ever.

I fixed my problem by adding return true; at the beginning of function valid() so it is definitely an artificial PouchDB imposed limitation for Cordova users. Now I can run PouchDB 5.4.4 (with the above mod to valid.js) on iOS 9.3.2 using the faster WKWebView + cordova-plugin-sqlite-2. Boom.

This may fix @tropperstyle 's issue in #5386 too.