编译Swift源文件挂在大型数组reduce-combine +表达式上

Question

在我的测试中，我习惯于在不同行的数组中编写字符串，例如

    let jsonString = ["{"
        ,"\"url\": \"http://localhost:8090/rest/api/3\","
        , "\"id\": \"3\","
        , "\"description\": \"A test that needs to be done.\","
        , "\"name\": \"Test\","
        , "\"subtest\": false,"
        , "\"avatar\": 1"
        ,"}"].reduce("", combine: +)

效果很好，但我的数组仍可为大型测试json字符串获得145行。 145行（或者可能更少，没有逐行尝试）在“编译Swift源文件”时挂起了构建任务。

首先，这有点疯狂。 30行还可以，145行不行？ 什么？

其次，有什么更好的解决方案在Swift中以多行形式编写String？ -我不想加载json并从外部文件中解析它。

Answer 1

这可能是因为类型推断。

尝试为数组变量赋予显式[String]类型，以帮助编译器解决该问题，然后将reduce应用于该变量。

let arrayOfStrings: [String] = ["{"
    ,"\"url\": \"http://localhost:8090/rest/api/3\","
    , "\"id\": \"3\","
    , "\"description\": \"A test that needs to be done.\","
    , "\"name\": \"Test\","
    , "\"subtest\": false,"
    , "\"avatar\": 1"
    ,"}"] // etc

let jsonString = arrayOfStrings.reduce("", combine: +)

无论如何，要创建JSON，您应该制作一个字典，然后使用NSJSONSerialization对其进行序列化，这样不容易出错：

迅捷2

do {
    // Create a dictionary.
    let dict = ["url": "http://localhost:8090/rest/api/3", "id": "3"]  // etc

    // Encode it to JSON data.
    let jsonData = try NSJSONSerialization.dataWithJSONObject(dict, options: [])

    // Get the object back.
    if let jsonObject = try NSJSONSerialization.JSONObjectWithData(jsonData, options: []) as? [String:String] {
        print(jsonObject)
    }

    // Get it as a String.
    if let jsonString = String(data: jsonData, encoding: NSUTF8StringEncoding) {
        print(jsonString)
    }

} catch let error as NSError {
    print(error)
}

迅捷3

do {
    // Create a dictionary.
    let dict = ["url": "http://localhost:8090/rest/api/3", "id": "3"]  // etc

    // Encode it to JSON data.
    let jsonData = try JSONSerialization.data(withJSONObject: dict, options: [])

    // Get the object back.
    if let jsonObject = try JSONSerialization.jsonObject(with: jsonData, options: []) as? [String:String] {
        print(jsonObject)
    }

    // Get it as a String.
    if let jsonString = String(data: jsonData, encoding: String.Encoding.utf8) {
        print(jsonString)
    }

} catch let error as NSError {
    print(error)
}