PouchDB put call getting 409: Document update conflict - backbone.js

Question

stack:nodejs, backbone.js v1.3.3, underscore.js v1.8.3, JQuery v2.2.4, cordova v6.1.1, https://pouchdb.com/download.html v6.0.5, https://github.com/jo/backbone-pouch v?, https://github.com/apache/cordova-plugin-device
I've polled the todos-db for the record using the _id and updated the _rev attribute, but I can't find my way out of these conflicts, so all help appreciated:
In my TodoModel, I'm doing:
return Backbone.Model.extend( {
idAttribute: "_id",
db: new PouchDB( "todos-db" ),
sync: this.BackbonePouch.sync( {
db: this.db,
fetch: "query",
options: {
query: {
include_docs: true
}
}
} ),
initialize: function(){
this.listenTo( Backbone, "updateRec", function( model ){
this.updateRec( model );
} );
},
updateRec: function( revRec ){
var self = this;
console.log( "revRec:", revRec );
this.db.get( revRec._id, { conflicts: true } ).then( function( doc ){
console.log( "doc:", doc ); // doc has no conflicts
revRec._rev = doc._rev;
return self.db.put( revRec );
} ).then( function( result ){
console.log( "updateRec result:", result );
return result;
} ).catch( function( err ){
// TODO: the above 'put' is throwing multiple confict errors, yet the db is updating after 7 tries
console.log( err );
} );
}
} );
});
In the log, revRec gives me:
_id:"2016-09-27T16:45:34.297Z"
_rev:"5-b554a2b4989efedac3ca3ccb679aa42e"
completed:false
delegatedTo:"Jen"
due:"Friday"
priority:"A"
project:"home"
task:"MBath concept"
The 'put' result gives me:
{ok: true, id: "2016-09-27T16:45:34.297Z", rev: "6-c6647848d965c35c7ac4f968cac7a91b"}
and the catch err is:
CustomPouchError {status: 409, name: "conflict", message: "Document update conflict", error: true}

Answer 1

You might want to look into pouchdb-upsert or read about conflicts.
In your code, I believe your particular error most likely stems from race conditions in requesting the same document multiple times (e.g. if the user clicks very quickly?). pouchdb-upsert would automatically handle such errors for you.