Type aliases for readability in Swift - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a type alias named Age for Int.

Swift

typealias [1] = Int

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ANumber

BAge

CInteger

DYears

Attempts:

3 left

💡 Hint

Common Mistakes

Using a name that is not descriptive of the type's purpose.

Trying to create an alias without the 'typealias' keyword.

The keyword typealias creates a new name for an existing type. Here, Age is the alias for Int.

2fill in blank

medium

Complete the code to define a type alias Coordinates for a tuple of two Double values.

Swift

typealias [1] = (Double, Double)

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APoint

BLocation

CCoordinates

DPosition

Attempts:

3 left

💡 Hint

Common Mistakes

Using a name that does not imply a pair of values.

Forgetting to use parentheses for the tuple type.

The alias Coordinates clearly represents a tuple of two Double values, often used for x and y positions.

3fill in blank

hard

Fix the error in the code by completing the type alias for a closure that takes an Int and returns a Bool.

Swift

typealias [1] = (Int) -> Bool

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AIntPredicate

BCheckNumber

CNumberCheck

DBoolClosure

Attempts:

3 left

💡 Hint

Common Mistakes

Using a name that does not clearly indicate a boolean test.

Confusing the order of parameters and return type.

The alias IntPredicate is a common name for a closure that tests an Int and returns a Bool.

4fill in blank

hard

Fill both blanks to create a type alias JSONDictionary for a dictionary with String keys and Any values.

Swift

typealias [1] = [[2]: Any]

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AJSONDictionary

BString

CInt

DAnyObject

Attempts:

3 left

💡 Hint

Common Mistakes

Using Int as dictionary keys instead of String.

Using AnyObject instead of Any for values.

The alias JSONDictionary represents a dictionary with String keys and values of any type, useful for JSON data.

5fill in blank

hard

Fill all three blanks to create a type alias CompletionHandler for a closure that takes a Bool, an optional String, and returns Void.

Swift

typealias [1] = ([2], [3]) -> Void

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ACompletionHandler

BBool

CString?

DVoid

Attempts:

3 left

💡 Hint

Common Mistakes

Using non-optional String instead of optional.

Incorrect order of parameters in the closure.

The alias CompletionHandler defines a closure taking a Bool and an optional String, returning nothing (Void).