Swift ランタイムで簡単に JavaScript を実行できる JavaScriptCore を Swift で使うための基礎のお話です。Swift と JavaScript の相互運用が簡単にできて面白いです。この資料は 2016/08/20 に iOSDC 2016 で発表したものになります。

4. for (var index in lines)
{
var line = lines[index];
var itemContent;
if (line.match(expression))
{
itemContent = RegExp.$2;
}
var outputItem = core.escapeHtml(itemContent);
return outputItems.map(convertToTag).join('n');
}

12. #iOSDC

16. 関数
クラス型
変数
文字列
変数

26. import JavaScriptCore

27. let context = JSContext()!

28. context.evaluateScript("var v1 = 10")
context.evaluateScript("var v2 = 20")
context.evaluateScript("var v3 = v1 + v2")

29. let value = context.objectForKeyedSubscript("v3")!
print("Answer = ", value) // Answer = 30
// 指定した名前が存在しない場合は undefined
let value = context.objectForKeyedSubscript("vX")!
print("Answer = ", value) // Answer = undefined

30. let answer = context.evaluateScript("v1 + v2")

33. let value: JSValue

34. •toInt32() -> Int32
•toUInt32() -> UInt32
•toDouble() -> Double
•toNumber() -> NSNumber!
•toString() -> String!
•toBool() -> Bool!
•toObject() -> Any!
•toDate() -> Date!
•toArray() -> [Any]!
•toDictionary() -> [AnyHashable : Any]!

35. •isNumber
•isString
•isBoolean
•isObject
•isUndefined
•isNull
•isArray
•isDate

36. let article: JSValue =
context.evaluateScript("article")!
// プロパティの参照
let title = article.forProperty("title")
// JavaScript メソッドの実行
let note = article.invokeMethod("getDescription",
withArguments: [])

37. let value1: JSValue =
context.objectForKeyedSubscript("v1")!
let value2: JSValue =
context.objectForKeyedSubscript("v2")!
if value1 == value2 {
}

40. •parseInt
•parseFloat
•encodeURI
•decodeURI
•encodeURIComponent
•decodeURIComponent
•encodeURI
•eval
•escape
•Object
•Array
•Date
•Math
•RegEx
•JSON
•Error

43. context.evaluateScript("var timeout = 5.0")

44. let account = "@es_kumagai"
// Swift 変数 account を、JavaScript に変数 name で登録
context.setObject(account,
forKeyedSubscript: "name" as NSString)

45. context.evaluateScript(
"function getAttribute(name) {" +
" return attributes[name];" +
"}")

46. let output : @convention(block) (String) -> Void = {
NSLog("(account) : ($0)")
}
// クロージャーを AnyObject 型にキャストして登録
context.setObject(
unsafeBitCast(output, to: AnyObject.self),
forKeyedSubscript: "output" as NSString)

47. context.evaluateScript(
"function Article(title, body) {" +
" this.title = title;" +
" this.body = body;" +
"}" +
"" +
"Article.prototype.getDescription = " +
" function() {" +
" return this.body.substr(0, 10);" +
"};")

48. @objc protocol ImageInterface : JSExport {
var width: Int { get set }
var height: Int { get set }
// インスタンス化をしたい場合は静的メソッドも宣言
static func make(name: String, scale: CGFloat)
-> AnyObject
}

49. class Image : NSObject, ImageInterface {
var width, height: Int
required init(name: String, scale: CGFloat) {…}
class func make(name: String, scale: CGFloat)
-> AnyObject {
return self.init(name: name, scale: scale)
}

50. let image = Image(name: "Profile", scale: 0.8)
context.setObject(image,
forKeyedSubscript: "icon" as NSString)

51. context.setObject(Image.self,
forKeyedSubscript: "Image" as NSString)
// メソッドは、全てのラベルを名前に含めて実行すること
context.evaluateScript(
"var banner = " +
"Image.makeWithNameScale('picture', 0.5)")

54. context.evaluateScript(
"function Article(title, body) {" +
" this.title = title;" +
" this.body = body;" +
"}" +
"" +
"Article.prototype.getDescription = " +
" function() {" +
" return this.body.substr(0, 10);" +
"};")

58. let path = Bundle.main.url(
forResource: "JavaScriptAPI",
withExtension: "js")!
let source = try! String(contentsOf: path)
// 読み込んだ JavaScript をコンテキストで実行
let context = JSContext()!
context.evaluateScript(source)