You have a class property declared as var data: String! which is set asynchronously after initialization. How should you safely use data in a method to avoid runtime crashes?
hard📝 Application Q15 of 15
Swift - Optionals
You have a class property declared as var data: String! which is set asynchronously after initialization. How should you safely use data in a method to avoid runtime crashes?
AForce unwrap <code>data!</code> without checking
BUse <code>print(data)</code> directly without checks
CChange <code>data</code> to a non-optional String
DUse <code>if data != nil { print(data) }</code> to check before use
Step-by-Step Solution
Solution:
Step 1: Understand asynchronous setting of implicitly unwrapped optional
Since data is set later, it may be nil when accessed early.
Step 2: Use safe check before accessing
Checking if data != nil ensures data is set before use, avoiding runtime crash.
Final Answer:
Use if data != nil { print(data) } to check before use -> Option D
Quick Check:
Check nil before using implicitly unwrapped optional set later [OK]
Quick Trick:Always check nil before using async-set implicitly unwrapped optional [OK]
Common Mistakes:
Using implicitly unwrapped optional without nil check
Changing type unnecessarily
Forcing unwrap without safety
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