Nit: here you can just have:
```js
exports.isActive = function isActive(addonId) {
  return getAddon(addonId).then(addon => addon.isActive && !addon.appDisabled);
}
```

You could also have:
```js
exports.isActive = function isActive(addonId)
  getAddon(addonId).then(addon => addon.isActive && !addon.appDisabled);
```

And:

```js
exports.isActive = addonId => 
  getAddon(addonId).then(addon => addon.isActive && !addon.appDisabled);
```

In the last one we missed the function's name, but I don't think we have any guidelines for that atm.