JiaLiPassion aeb6d0d0f7 fix(zone.js): should not try to patch fetch if it is not writable (#36311)
Close #36142

In Firefox extensions, the `window.fetch` is not configurable, that means

```
const desc = Object.getOwnPropertyDescriptor(window, 'fetch');
desc.writable === false;
```

So in this case, we should not try to patch `fetch`, otherwise, it will
throw error ('fetch is ReadOnly`)

PR Close #36311
2020-04-06 15:34:34 -07:00
..