{"action":"opened","issue":{"url":"https://api.github.com/repos/6to5/6to5/issues/524","labels_url":"https://api.github.com/repos/6to5/6to5/issues/524/labels{/name}","comments_url":"https://api.github.com/repos/6to5/6to5/issues/524/comments","events_url":"https://api.github.com/repos/6to5/6to5/issues/524/events","html_url":"https://github.com/6to5/6to5/issues/524","id":54689065,"number":524,"title":"Flow-style optional parameters throw syntax error","user":{"login":"ianobermiller","id":897931,"avatar_url":"https://avatars.githubusercontent.com/u/897931?v=3","gravatar_id":"","url":"https://api.github.com/users/ianobermiller","html_url":"https://github.com/ianobermiller","followers_url":"https://api.github.com/users/ianobermiller/followers","following_url":"https://api.github.com/users/ianobermiller/following{/other_user}","gists_url":"https://api.github.com/users/ianobermiller/gists{/gist_id}","starred_url":"https://api.github.com/users/ianobermiller/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/ianobermiller/subscriptions","organizations_url":"https://api.github.com/users/ianobermiller/orgs","repos_url":"https://api.github.com/users/ianobermiller/repos","events_url":"https://api.github.com/users/ianobermiller/events{/privacy}","received_events_url":"https://api.github.com/users/ianobermiller/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":0,"created_at":"2015-01-18T07:24:18Z","updated_at":"2015-01-18T07:24:18Z","closed_at":null,"body":"```js\r\nfunction a(b?: Object) {}\r\n```\r\n\r\nSince you will often use a default parameter anyway a possible workaround is:\r\n\r\n```js\r\nfunction a(b: Object = {}) {}\r\n```\r\n\r\nFlow documentation: http://flowtype.org/docs/functions.html#function-based-type-annotations"}}