No Magic Numbers

Magic numbers should be replaced by named constants

  • Identifier: no_magic_numbers
  • Enabled by default: No
  • Supports autocorrection: No
  • Kind: idiomatic
  • Analyzer rule: No
  • Minimum Swift compiler version: 5.0.0
  • Default configuration:
    KeyValue
    severity warning
    test_parent_classes [“QuickSpec”, “XCTestCase”]
    allowed_numbers [0.0, 1.0, 100.0]

Non Triggering Examples

var foo = 123

static let bar: Double = 0.123

let a = b + 1.0

array[0] + array[1] 

let foo = 1_000.000_01

// array[1337]

baz("9999")

func foo() {
    let x: Int = 2
    let y = 3
    let vector = [x, y, -1]
}

class A {
    var foo: Double = 132
    static let bar: Double = 0.98
}

@available(iOS 13, *)
func version() {
    if #available(iOS 13, OSX 10.10, *) {
        return
    }
}

enum Example: Int {
    case positive = 2
    case negative = -2
}

class FooTests: XCTestCase {
    let array: [Int] = []
    let bar = array[42]
}

class FooTests: XCTestCase {
    class Bar {
        let array: [Int] = []
        let bar = array[42]
    }
}

class MyTest: XCTestCase {}
extension MyTest {
    let a = Int(3)
}

extension MyTest {
    let a = Int(3)
}
class MyTest: XCTestCase {}

let foo = 1 << 2

let foo = 1 >> 2

let foo = 2 >> 2

let foo = 2 << 2

let a = b / 100.0

let range = 2 ..< 12

let range = ...12

let range = 12...

let (lowerBound, upperBound) = (400, 599)

let a = (5, 10)

let notFound = (statusCode: 404, description: "Not Found", isError: true)

#Preview { ContentView(value: 5) }

@Test func f() { let _ = 2 + 2 }

@Suite struct Test {
    @Test func f() {
        func g() { let _ = 2 + 2 }
        let _ = 2 + 2
    }
}

@Suite actor Test {
    private var a: Int { 2 }
    @Test func f() { let _ = 2 + a }
}

class Test { // @Suite implicitly
    private var a: Int { 2 }
    @Test func f() { let _ = 2 + a }
}

#if compiler(<6.0) && compiler(>4.0)
let a = 1
#elseif compiler(<3.0)
let a = 2
#endif

let myColor: UIColor = UIColor(red: 0.6, green: 1.0, blue: 0.2, alpha: 0.52)

let colorLiteral = #colorLiteral(red: 0.7019607843, green: 0.7019607843, blue: 0.7019607843, alpha: 1)

Triggering Examples

foo(↓321)

bar(↓1_000.005_01)

array[↓42]

let box = array[↓12 + ↓14]

let a = b + ↓2.0

let range = 2 ... ↓12 + 1

let range = ↓2*↓6...

let slice = array[↓2...↓4]

for i in ↓3 ..< ↓8 {}

let n: Int = Int(r * ↓255) << ↓16 | Int(g * ↓255) << ↓8

Color.primary.opacity(isAnimate ? ↓0.1 : ↓1.5)

        class MyTest: XCTestCase {}
        extension NSObject {
            let a = Int(↓3)
        }

if (fileSize > ↓1000000) {
    return
}

let imageHeight = (width - ↓24)

return (↓5, ↓10, ↓15)

#ExampleMacro {
    ContentView(value: ↓5)
}

#if compiler(<6.0) && compiler(>4.0)
f(↓6.0)
#elseif compiler(<3.0)
f(↓3.0)
#else
f(↓4.0)
#endif