ios - JSONSerialization 中的选项[]

Question

什么是 option: [] in JSONSerialization in swift

let jsonData = try JSONSerialization.data(withJSONObject: updatedJson, options: [])

Answer 1

JSONSerialization.WritingOptions是一个 OptionSet并符合 ExpressibleByArrayLiteral协议(protocol)，这意味着可以将“选项集”指定为数组文字。例如:

let jsonData = try JSONSerialization.data(withJSONObject: json,
                                         options: [.prettyPrinted, .sortedKeys])

特别是，空数组文字意味着“没有选择”:

let jsonData = try JSONSerialization.data(withJSONObject: json, options: [])

在这种特殊情况下，它等同于省略参数

let jsonData = try JSONSerialization.data(withJSONObject: json)

因为它有一个默认值[]:

class func data(withJSONObject obj: Any, 
    options opt: JSONSerialization.WritingOptions = []) throws -> Data