This API is available on Firefox OS for internal applications only.

The add() method of the DataStore interface adds a new record to the data store; if the record you are attempting to add already exists, it will throw an exception.

Note: The Data Store API is available in Web Workers, from Firefox 32 onwards (Firefox OS 2.0; see bug 949325.)


store.add(object).then(function(id) {
  // Do something with id, which is the id of the record added to the data store


A Promise object of type DataStoreKey that resolves with a ID number identifying the record added to the store.


The object you want to add to the data store.
You can specify an optional second parameter that will be a DataStoreKey of type unsigned long or DOMString, if you want to give the added record a specific id. If you don't specify this, the object's id will be numeric (auto incremented).
You can specify an optional third parameter that will be a revisionId (a DOMString). This can be used to prevent conflicts. If the revisionId is not the current revisionId for the current Data Store, the operation is aborted. This means that the developer has a 'old' revisionId and will have to manage the conflict somehow.


The following example function takes the current data store and an object to be added to the data store as arguments, adds the object to the store, and then creates a table row to display the object data in the app and appends it to an existing table in the DOM:

function addContact(store, obj) {
  store.add(obj).then(function(id) {
    var tableRow = document.createElement('tr');
    tableRow.innerHTML = '<td>' + obj.lName +
                         '</td><td>' + obj.fName +
                         '</td><td>' + +
                         '</td><td>' + +
                         '</td><td>' + obj.address + '</td>';
    var myId = id;
    tableRow.setAttribute('data-id', myId);
    tableRow.onclick = function(event) {

Note: To see this function working inside a complete example, check out our Data Store Contacts Editor example.


Specification Status Comment
Data Store API Draft  

Note that add() isn't currently defined in the spec, but this should be updated soon. It will replace the now-deprecated insert() method.

The discussion concerning this API's creation happened in various Mozilla mailing lists and other places. A summary of the discussion and further pointers can be found on the Mozilla Wiki. For further feedback and questions, send mail to the dev-webapi mailing list.

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
Basic support No support No support No support No support No support
Feature Android Chrome Firefox Mobile (Gecko) Firefox OS IE Phone Opera Mobile Safari Mobile
Basic support No support No support No support 1.0.1 No support No support No support
Available in web workers No support No support No support 2.0 No support No support No support

See also

Document Tags and Contributors

 Contributors to this page: chrisdavidmills, fscholz
 Last updated by: chrisdavidmills,