how to override enum value based on the key in typescript

Question

I have one based enum like BasedColor that I would like to use on other enum as AnotherState. If there is anyway to override the value with the same key. so I do not need to duplicate the key code . I guess I can create a new enum and duplicated the key abd assign to another value. but I am wondering if there is a better way to do it in typescript

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

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

Answer 1

enums in TS are just objects. So, you can assign them to interfaces that they conform to, and you can "extend" one using the spread operator ....

// 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'
}

Now we can see how extending works:

// 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};

This way you get inherited values but never have to rewrite the underlying enum, which can lead to unexpected behavior since enums are supposed to be constant after definition.

Answer 2

You can do it like this:

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

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

console.log(Colors.First)