Question

我有一个检查请求数据以访问api端点的功能。对于每个端点，此特定端点可以有不同的预加载数据。

问题是，对于每个操作，我都需要将请求数据转换为端点数据类型。有没有一种方法可以只对case块范围断言一次？或者我应该采取一些不同的方法。

C:\Users\>flutter doctor

    Doctor summary (to see all details, run flutter doctor -v):
    [√] Flutter (Channel stable, v1.12.13+hotfix.5, on Microsoft Windows [Version 10.0.18362.535], locale en-IN)
    [X] Android toolchain - develop for Android devices
        X Unable to locate Android SDK.
          Install Android Studio from: https://developer.android.com/studio/index.html
          On first launch it will assist you in installing the Android SDK components.
          (or visit https://flutter.dev/setup/#android-setup for detailed instructions).
          If the Android SDK has been installed to a custom location, set ANDROID_HOME to that location.
          You may also want to add it to your PATH environment variable.

    [√] Android Studio (version 3.5)
    [!] Connected device
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    ! Doctor found issues in 2 categories.

UPD。 Variant that jared suggested。

Answer 1

根据您的用例的具体情况，您可能对discriminated unions感兴趣：


type Req = { endpoint: "endpoint1", data: string }
    | { endpoint: "endpoint3" | "endpoint2", data: number }

const checkRole = (_req: unknown): boolean => {
    let req = _req as Req;
    switch (req.endpoint) {
        case 'endpoint1': {
            if (req.data = 'hi') return true
            return false;
        }
        case 'endpoint3':
        case 'endpoint2': {
            req.data += 1;
            req.data *= 1;
            req.data -= 1;
            if (req.data == 5) return true
        }
        default: return false
    }
}

Playground Link

Typescript有没有一种方法可以在switch中转换大小写类型？

1 个答案: