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Modern Swift
Result builders Property wrappers Key paths Codable JSONDecoder Result type Pattern matching if case Availability checks
Swift / Modern Swift

Availability checks

Learn availability checks in Swift through a focused explanation, a dedicated topic-specific example, an engineering boundary, and a mastery check.

12 min read • Advanced

availability checks is an atomic Swift topic inside Modern Swift. The example uses the named construct directly so you can see its syntax, data flow, and observable behavior.

Read the code by locating the exact feature named availability checks, then trace the value before and after that feature runs. This lesson is intentionally isolated from neighboring topics: changing identifiers alone would not reproduce the same behavior because the construct itself is different.

Topic-specific example

swift-0080-45d8164534.swift
swift Try It Live 
if #available(macOS 12, *) { print("modern API available") } else { print("fallback") }
Edge case / engineering note

For availability checks, test the boundary that makes the feature meaningful: invalid input, an empty value, a missing branch, lifecycle/cleanup, or a type/runtime constraint. Do not infer correctness only from the happy path.

Content source & attribution
Original Syntaxis Content · Original Syntaxis Content

Lesson quizzes

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Pattern matching if case