IE8: Object doesn't support this property or method

Unfortunately it looks like the fix for the property names was not enough to fix IE8. Calling any localforage method (I tried setItem, getItem and clear) results in an error Object doesn't support this property or method. I think it would be worthwhile spending time on getting the test suite running on some cross-browser cloud testing provider. This is an open source project so getting a free account should be easy (I myself just made an account and contacted their customer support asking to activate the open source plan). Saucelabs is also free for open source.

Having had my own tests run in the cloud for a suite of browsers for every PR has at least made me feel much more confident about making changes, so I highly recommend. :) I can also do my best to help if you have questions, but my previous setups have been quite homogenous and different from yours (gulp, karma, mocha, expect.js), so my knowledge will probably only be partially applicable here.

Start by reproducing the IE8 error with localforage's setItem, getItem, and clear methods, then inspect the existing Gulp, Karma, Mocha, and expect.js test setup. Done means these methods work in IE8 and the test suite runs against a cross-browser cloud provider such as Sauce Labs.