{"action":"created","issue":{"url":"https://api.github.com/repos/facebook/react-native/issues/3877","labels_url":"https://api.github.com/repos/facebook/react-native/issues/3877/labels{/name}","comments_url":"https://api.github.com/repos/facebook/react-native/issues/3877/comments","events_url":"https://api.github.com/repos/facebook/react-native/issues/3877/events","html_url":"https://github.com/facebook/react-native/issues/3877","id":114949941,"number":3877,"title":"development-level warning are ON, performance optimizations are OFF'","user":{"login":"hahaGitHub","id":12423630,"avatar_url":"https://avatars.githubusercontent.com/u/12423630?v=3","gravatar_id":"","url":"https://api.github.com/users/hahaGitHub","html_url":"https://github.com/hahaGitHub","followers_url":"https://api.github.com/users/hahaGitHub/followers","following_url":"https://api.github.com/users/hahaGitHub/following{/other_user}","gists_url":"https://api.github.com/users/hahaGitHub/gists{/gist_id}","starred_url":"https://api.github.com/users/hahaGitHub/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/hahaGitHub/subscriptions","organizations_url":"https://api.github.com/users/hahaGitHub/orgs","repos_url":"https://api.github.com/users/hahaGitHub/repos","events_url":"https://api.github.com/users/hahaGitHub/events{/privacy}","received_events_url":"https://api.github.com/users/hahaGitHub/received_events","type":"User","site_admin":false},"labels":[],"state":"closed","locked":false,"assignee":null,"milestone":null,"comments":1,"created_at":"2015-11-04T01:39:41Z","updated_at":"2015-11-04T01:56:20Z","closed_at":"2015-11-04T01:56:20Z","body":"i pod install react in my own project.and i use RCTRootView to create my UIView.then some information display,as below:\r\n[info][tid:com.facebook.React.JavaScript] 'Running application \"TestUI\" with appParams: {\"rootTag\":21,\"initialProps\":{}}. __DEV__ === true, development-level warning are ON, performance optimizations are OFF'\r\ncould you tell me what is the meaning of that?thanks."},"comment":{"url":"https://api.github.com/repos/facebook/react-native/issues/comments/153546431","html_url":"https://github.com/facebook/react-native/issues/3877#issuecomment-153546431","issue_url":"https://api.github.com/repos/facebook/react-native/issues/3877","id":153546431,"user":{"login":"ide","id":379606,"avatar_url":"https://avatars.githubusercontent.com/u/379606?v=3","gravatar_id":"","url":"https://api.github.com/users/ide","html_url":"https://github.com/ide","followers_url":"https://api.github.com/users/ide/followers","following_url":"https://api.github.com/users/ide/following{/other_user}","gists_url":"https://api.github.com/users/ide/gists{/gist_id}","starred_url":"https://api.github.com/users/ide/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/ide/subscriptions","organizations_url":"https://api.github.com/users/ide/orgs","repos_url":"https://api.github.com/users/ide/repos","events_url":"https://api.github.com/users/ide/events{/privacy}","received_events_url":"https://api.github.com/users/ide/received_events","type":"User","site_admin":false},"created_at":"2015-11-04T01:56:20Z","updated_at":"2015-11-04T01:56:20Z","body":"It's telling you that you're in development mode which means: there are warnings, and performance will be slower. When you load the JS bundle with ?dev=false, you won't get warnings and your JS performance will be faster."}}