Issue encountered when attempting to assign a local variable as the initial value of an enum object member

Check out this playground link for a TypeScript example.

I'm having issues setting the initial value of an enum member using a constant numeric value. Unfortunately, all subsequent values give an error stating "Enum member must have initializer."

Is there a restriction on doing this? Why aren't the following members automatically set to the previous member plus one?

Here's the code in question (also available in the provided playground link):

const firstValue: number = 100;
enum Animal {
    Lion = firstValue,
    Tiger,  
    Horse,  
    Fish    
}

Answer №1

Currently, it is not permitted to follow another enum member with an initializer. The auto-increment of an enum member only occurs when the computed value is statically known. Currently, this includes numeric literals and other enum members whose values are statically known, but const declarations are not included in the analysis.

To work around this issue, you can do the following:

enum FirstValue {
    firstValue = 100
}

Then, use FirstValue.firstValue instead of firstValue.

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