如何根据打字稿中的键覆盖枚举值

Question

我有一个像BasedColor 这样的基于枚举，我想在其他枚举上用作AnotherState。如果无论如何要使用相同的键覆盖该值。所以我不需要复制密钥代码。我想我可以创建一个新的枚举并将键 abd 分配给另一个值。但我想知道在打字稿中是否有更好的方法来做到这一点

enum BasedColor 
{
    First= 'red',
    Second = 'blue'
}

enum AnotherState
{
    First= 'light red',
    Second = 'light blue'
    Third = 'from another state third keu'
}

Answer 1

你可以这样做：

enum Colors
{
    First= 'red',
    Second = 'blue'
}

(Colors as any)['First'] = "Dark Red" // <== here

console.log(Colors.First)

Answer 2

TS 中的枚举只是对象。因此，您可以将它们分配给它们符合的接口，并且可以使用扩展运算符...“扩展”一个。

// An interface for the keys a State can have
interface StateKeys {
    first: string;
    second: string;
    third?: string;
}

// Our base state, which we'll extend
enum BaseState {
    first = 'blue',
    second = 'red',
    third = 'magenta'
}

// Our custom state
enum AnotherState {
    first = 'light blue',
    second = 'light red'
}

现在我们可以看到扩展是如何工作的：

// For the example, we'll just print the state's values
function doSomething() {
    console.log(currentState.first, currentState.second, currentState.third);
}

// Start with our state as the base state
let currentState: StateKeys = BaseState

doSomething(); // Prints "blue, red, magneta"

// Now we extend our base state with another state.
// Note, keys/values in objects to the right will overwrite ones to the left
currentState = {...BaseState, ...AnotherState};

doSomething(); // Prints "light blue, light red, magenta"

// You could also extend the *current* state instead:
currentState = {...currentState, ...AnotherState};

通过这种方式，您可以获得继承的值，但不必重写底层枚举，这可能会导致意外行为，因为枚举在定义后应该是常量。