Roarke Gaskill
So you want to programarically delete your IndexedDb client-side datastore. It is actually pretty easy. Just call deleteDatabae like so:
window.indexedDB.deleteDatabase('some_database_name');An important item to be a aware of is the promise that is returned from the deleteDatabase method will not complete until all the other connections to the database are closed. I have created a simple testacular test here to illistrate this. To run this test pull the repository and run using testacular.
git clone git@github.com:rgaskill/indexeddb-test.git
## If testacular isn't installed
npm install -g testacular
cd indexeddb-test
testacular startThe test is currently configured to run in chrome but it will run in Firefox as well. If you want to run the test in Firefox update the testacular.conf.js
//replace
browsers = ['Chrome'];
//with
browsers = ['Firefox'];The Tests
In the test/IndexedDbSpec.js file you will see a few brief tests. Listed below is a brief overview of the tests.
it(“should delete database after explicit close”, function() {
In this test the first “runs” function opens a connection to the database and then the second “runs” function deletes the database. If you were to comment out line 34 (db.close();) this test would timeout waiting for the databaseDelete promise to complete. The runs functions are a Jasmine construct to allow code to be run serially.
runs(function(){
db.close(); //EXPLICIT DB CLOSE
var request = window.indexedDB.deleteDatabase(dbName);
var done = false;
request.onerror = function(event) {
console.log("delete error", event);
done = true;
};
request.onsuccess = function(event) {
console.log("delete success", event);
done = true;
};
waitsFor(function() {
return done;
},5000);
});it(“should delete database after version change event”, function() {
In this test rather than closing the database explicitly prior to deleting the database I added a listener at line 76 (db.onversionchange = function(event) {) that is fired when the deleteDatabase is called. If the version property of the event is empty it is assumed the database is attempting to be deleted.
db.onversionchange = function(event) {
console.log("version change", event);
//empty version implies that the database is being deleted
if ( !event.version ){
db.close();
}
};describe(‘IndexedDb Test Template’, function() {
This is just a simple template to show one possible way to open a connection to the IndexedDb before each test and delete the IndexedDb test after each test is run.
beforeEach(function() {
runs(function() {
var done = false;
var request = window.indexedDB.open(dbName);
request.onerror = function(event) {
console.log("open error", event);
done = true;
};
request.onsuccess = function(event) {
console.log("open success", event);
db = this.result;
done = true;
};
waitsFor(function() {
return done;
},5000);
});
});
afterEach(function() {
runs(function(){
db.close();
var request = window.indexedDB.deleteDatabase(dbName);
var done = false;
request.onerror = function(event) {
console.log("delete error", event);
done = true;
};
request.onsuccess = function(event) {
console.log("delete success", event);
done = true;
};
waitsFor(function() {
return done;
},5000);
});
});Yeah, I am going to start sharing my thoughts. I don’t intend to spend any time pontificating about the state of the technology world. Primarily, I need a place to store my code snippets and notes.