我想用Swift声明一个参数,它有一个可选的闭包.我声明的函数如下所示:
class Promise {
func then(onFulfilled: ()->(), onReject: ()->()?){
if let callableRjector = onReject {
// do stuff!
}
}
}
但Swift 抱怨说,"条件中的绑定值必须是可选类型",其中声明了"if let".
我想用Swift声明一个参数,它有一个可选的闭包.我声明的函数如下所示:
class Promise {
func then(onFulfilled: ()->(), onReject: ()->()?){
if let callableRjector = onReject {
// do stuff!
}
}
}
但Swift 抱怨说,"条件中的绑定值必须是可选类型",其中声明了"if let".
您应该将可选闭包括在括号中.这将正确地确定?
操作员的范围.
func then(onFulfilled: ()->(), onReject: (()->())?){
if let callableRjector = onReject {
// do stuff!
}
}