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Merged
atdrendel merged 2 commits into from
Jun 25, 2026
Merged

Store nil JSON assignments as null #10

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e20ac52
Store nil JSON assignments as null
atdrendel Jun 25, 2026
96e4bde
Update GitHub Actions CI
atdrendel Jun 25, 2026
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10 changes: 5 additions & 5 deletions .github/workflows/ci.yml
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Original file line number Diff line number Diff line change
Expand Up @@ -4,11 +4,11 @@ on: push

jobs:
test:
runs-on: macos-14
runs-on: macos-26

steps:
- uses: actions/checkout@v3
- name: Select Xcode 16
run: sudo xcode-select -s /Applications/Xcode_16.0.app
- uses: actions/checkout@v4
- name: Select Xcode 26
run: sudo xcode-select -s /Applications/Xcode_26.5.app
- name: Test
run: swift test
10 changes: 10 additions & 0 deletions README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -27,6 +27,16 @@ json["one"].integerValue // 2
json["object"]["four_text"].stringValue // "four"
```

Swift `nil` maps to JSON `null` in literals and subscript assignments:

```swift
var object: JSON = ["name": "Blob"]
object["deleted_at"] = nil as JSON? // stores JSON.null
object.removeValue(forKey: "name") // removes the key
```

Missing keys return `nil` and are distinct from explicit JSON `null`.

## Installation

### Swift Package Manager
Expand Down
52 changes: 32 additions & 20 deletions Sources/JSON/JSON.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -27,11 +27,7 @@ public enum JSON:
}
set {
guard case var .dictionary(dict) = self else { return }
if let newValue {
dict[key] = newValue
} else {
dict.removeValue(forKey: key)
}
dict[key] = newValue ?? .null
self = .dictionary(dict)
}
}
Expand All @@ -46,7 +42,7 @@ public enum JSON:
if let newValue {
dict[key] = .array(newValue.compactMap(\.json))
} else {
dict.removeValue(forKey: key)
dict[key] = .null
}
self = .dictionary(dict)
}
Expand All @@ -62,7 +58,7 @@ public enum JSON:
if let newValue {
dict[key] = .boolean(newValue)
} else {
dict.removeValue(forKey: key)
dict[key] = .null
}
self = .dictionary(dict)
}
Expand All @@ -78,7 +74,7 @@ public enum JSON:
if let newValue {
dict[key] = .dictionary(newValue.compactMapValues(\.json))
} else {
dict.removeValue(forKey: key)
dict[key] = .null
}
self = .dictionary(dict)
}
Expand All @@ -94,7 +90,7 @@ public enum JSON:
if let newValue {
dict[key] = .number(newValue)
} else {
dict.removeValue(forKey: key)
dict[key] = .null
}
self = .dictionary(dict)
}
Expand All @@ -110,7 +106,7 @@ public enum JSON:
if let newValue {
dict[key] = .number(Double(newValue))
} else {
dict.removeValue(forKey: key)
dict[key] = .null
}
self = .dictionary(dict)
}
Expand All @@ -126,12 +122,20 @@ public enum JSON:
if let newValue {
dict[key] = .string(newValue)
} else {
dict.removeValue(forKey: key)
dict[key] = .null
}
self = .dictionary(dict)
}
}

@discardableResult
public mutating func removeValue(forKey key: String) -> JSON? {
guard case var .dictionary(dict) = self else { return nil }
let removedValue = dict.removeValue(forKey: key)
self = .dictionary(dict)
return removedValue
}

public subscript(index: Int) -> JSON? {
get {
guard case let .array(arr) = self, index < arr.count
Expand Down Expand Up @@ -373,7 +377,7 @@ public extension JSON? {
}
set {
guard case var .dictionary(dict) = self else { return }
dict[key] = newValue
dict[key] = newValue ?? .null
self = .dictionary(dict)
}
}
Expand All @@ -388,7 +392,7 @@ public extension JSON? {
if let newValue {
dict[key] = .array(newValue.compactMap(\.json))
} else {
dict.removeValue(forKey: key)
dict[key] = .null
}
self = .dictionary(dict)
}
Expand All @@ -404,7 +408,7 @@ public extension JSON? {
if let newValue {
dict[key] = .boolean(newValue)
} else {
dict.removeValue(forKey: key)
dict[key] = .null
}
self = .dictionary(dict)
}
Expand All @@ -420,7 +424,7 @@ public extension JSON? {
if let newValue {
dict[key] = .dictionary(newValue.compactMapValues(\.json))
} else {
dict.removeValue(forKey: key)
dict[key] = .null
}
self = .dictionary(dict)
}
Expand All @@ -436,7 +440,7 @@ public extension JSON? {
if let newValue {
dict[key] = .number(newValue)
} else {
dict.removeValue(forKey: key)
dict[key] = .null
}
self = .dictionary(dict)
}
Expand All @@ -452,7 +456,7 @@ public extension JSON? {
if let newValue {
dict[key] = .number(Double(newValue))
} else {
dict.removeValue(forKey: key)
dict[key] = .null
}
self = .dictionary(dict)
}
Expand All @@ -468,12 +472,20 @@ public extension JSON? {
if let newValue {
dict[key] = .string(newValue)
} else {
dict.removeValue(forKey: key)
dict[key] = .null
}
self = .dictionary(dict)
}
}

@discardableResult
mutating func removeValue(forKey key: String) -> JSON? {
guard case var .dictionary(dict) = self else { return nil }
let removedValue = dict.removeValue(forKey: key)
self = .dictionary(dict)
return removedValue
}

subscript(index: Int) -> JSON? {
get {
guard case let .array(arr) = self, index < arr.count
Expand Down Expand Up @@ -570,13 +582,13 @@ public extension JSON? {
}

static func == (_: NSNull, _ arg2: JSON?) -> Bool {
guard let arg2 else { return true }
guard let arg2 else { return false }
guard case .null = arg2 else { return false }
return true
}

static func == (_ arg1: JSON?, _: NSNull) -> Bool {
guard let arg1 else { return true }
guard let arg1 else { return false }
guard case .null = arg1 else { return false }
return true
}
Expand Down
116 changes: 116 additions & 0 deletions Tests/JSONTests/JSONTests.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -151,6 +151,109 @@ final class JSONTests: XCTestCase {
)
}

func testNilDictionarySubscriptAssignmentStoresNull() throws {
var object: JSON = [
"one": 1,
]

object["json_nil"] = nil as JSON?
object["array_nil"] = nil as [Any?]?
object["bool_nil"] = nil as Bool?
object["dictionary_nil"] = nil as [String: Any?]?
object["double_nil"] = nil as Double?
object["int_nil"] = nil as Int?
object["string_nil"] = nil as String?

XCTAssertEqual(JSON.null, object["json_nil"])
XCTAssertEqual(JSON.null, object["array_nil"])
XCTAssertEqual(JSON.null, object["bool_nil"])
XCTAssertEqual(JSON.null, object["dictionary_nil"])
XCTAssertEqual(JSON.null, object["double_nil"])
XCTAssertEqual(JSON.null, object["int_nil"])
XCTAssertEqual(JSON.null, object["string_nil"])
XCTAssertNil(object["missing"] as JSON?)
}

func testOptionalNilDictionarySubscriptAssignmentStoresNull() throws {
var object: JSON? = [
"one": 1,
]

object["json_nil"] = nil as JSON?
object["array_nil"] = nil as [Any?]?
object["bool_nil"] = nil as Bool?
object["dictionary_nil"] = nil as [String: Any?]?
object["double_nil"] = nil as Double?
object["int_nil"] = nil as Int?
object["string_nil"] = nil as String?

XCTAssertEqual(JSON.null, object["json_nil"])
XCTAssertEqual(JSON.null, object["array_nil"])
XCTAssertEqual(JSON.null, object["bool_nil"])
XCTAssertEqual(JSON.null, object["dictionary_nil"])
XCTAssertEqual(JSON.null, object["double_nil"])
XCTAssertEqual(JSON.null, object["int_nil"])
XCTAssertEqual(JSON.null, object["string_nil"])
XCTAssertNil(object["missing"] as JSON?)
}

func testRemoveValueForKey() throws {
var object: JSON = [
"one": 1,
"null": nil,
]

let number = object.removeValue(forKey: "one")
XCTAssertEqual(JSON.number(1), try XCTUnwrap(number))
XCTAssertNil(object["one"] as JSON?)

let null = object.removeValue(forKey: "null")
XCTAssertEqual(JSON.null, try XCTUnwrap(null))
XCTAssertNil(object["null"] as JSON?)

XCTAssertNil(object.removeValue(forKey: "missing"))

var string: JSON = "text"
XCTAssertNil(string.removeValue(forKey: "missing"))
XCTAssertEqual("text", string)
}

func testOptionalRemoveValueForKey() throws {
var object: JSON? = [
"one": 1,
"null": nil,
]

let number = object.removeValue(forKey: "one")
XCTAssertEqual(JSON.number(1), try XCTUnwrap(number))
XCTAssertNil(object["one"] as JSON?)

let null = object.removeValue(forKey: "null")
XCTAssertEqual(JSON.null, try XCTUnwrap(null))
XCTAssertNil(object["null"] as JSON?)

XCTAssertNil(object.removeValue(forKey: "missing"))

var missingObject: JSON?
XCTAssertNil(missingObject.removeValue(forKey: "missing"))
XCTAssertNil(missingObject)
}

func testRemoveValueForKeyThroughNestedSubscript() throws {
var object: JSON = [
"dict": [
"key": "value",
"keep": true,
],
]

let removedValue = object["dict"].removeValue(forKey: "key")

XCTAssertEqual("value", try XCTUnwrap(removedValue))
XCTAssertNil(object["dict"]["key"] as JSON?)
XCTAssertEqual(true, object["dict"]["keep"])
}

func testRawValue() throws {
let arr = try XCTUnwrap(JSON(["one", nil, 123, 1.23]).rawValue as? [Any?])
XCTAssertEqual("one", arr[0] as? String)
Expand Down Expand Up @@ -259,6 +362,19 @@ final class JSONTests: XCTestCase {
XCTAssertTrue(JSON.string("boom") as JSON? == "boom")
}

func testNSNullComparisonDistinguishesExplicitNullFromMissingValue() throws {
let object: JSON = [
"explicit_null": nil,
]

XCTAssertTrue(NSNull() == object["explicit_null"])
XCTAssertTrue(object["explicit_null"] == NSNull())

XCTAssertNil(object["missing"] as JSON?)
XCTAssertFalse(NSNull() == object["missing"])
XCTAssertFalse(object["missing"] == NSNull())
}

func testCodable() throws {
let json: JSON = [
"one": 2,
Expand Down
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