Handle the error

Handle the error

• 1.
  @kamidude
• 2.
  @kamidude ERRORS types & debugging NSErrorconforms Error
 Error is convertible to NSError *
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  @kamidude STOPPING EXECUTION objc can@catch exceptions / swift cannot only fatalError is kept on -Ounchecked *
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  @kamidude SWIFT ERRORS * Everytype can adopt Error basics - conforming
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  @kamidude SWIFT ERRORS Functions Only ComputedProperties Subscript basics - throwing errors *
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  @kamidude SWIFT ERRORS basics -catching errors catch can match pattern swift errors are not exceptions ! *
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  @kamidude SWIFT ERRORS common error- ignoring errors * never ignore errors
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  @kamidude SWIFT ERRORS advanced -rethrowing non-throwing is a specific 
 case of throwing func *
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  @kamidude SWIFT ERRORS advanced -result equivalency
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  @kamidude SWIFT ERRORS advanced -result equivalency
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  @kamidude SWIFT ERRORS advanced -result equivalency
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  @kamidude ERRORS handling strategies My ownrules of thumb Adapt to your use case Expected Unexpected Domain • Handle in the application code • Display details to the user • Don’t log the error • Raise an error • Display details to the user • Log the error Technical • Handle in the application code • Don’t display details to the user • Don’t log the error • Raise an error • Don’t display details to the user • Log the error Domain vs Technical / Expected vs Unexpected http://www.blueskyline.com/ErrorPatterns/ErrorPatternsPaper.pdf
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  @kamidude ERRORS error semantic -handling strategies Retry Silently - Not a solution : if the retry fails, you have to handle the error eventually - Exponential backoff 👍 Easy 👎 Not a real solution My own rules of thumb Adapt to your use case
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  @kamidude ERRORS error semantic -handling strategies Ask user to retry / cancel - Modally or not - Basic strategy : prevent access to content 👍 Easy 👎 Poor UX My own rules of thumb Adapt to your use case
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  @kamidude ERRORS error semantic -handling strategies Optimistic update - Show updated local UI - Works for user actions, not fetching 👍 User friendly / works in most cases 👎 Involves complex synchronization / client logic My own rules of thumb Adapt to your use case
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  @kamidude ERRORS error semantic -handling strategies Crash - Intended or not 👍 Get info through CrashReporter & fix 👎 Not very user friendly My own rules of thumb Adapt to your use case
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  @kamidude THANK YOU questions ?