CODEWITHSUNDEEP
javascripttypescriptenums
Eli
Eli

Reputation: 857

Why does typescript allow number entry in an enum if one value is set to a number?

 enum Type{
    Video, 
    BlogPost = "BLOG_POST", 
    Quiz = "QUIZ"
}

I have the following code in type script, if I have a function createContent

const createContent = (contentType:Type) => {
    console.log(contentType)
}

and call this function using

createContent(10)

this works. However, if all enum types are set to strings in the following code it does not allow a number to be passed in. Why is this?

enum Type{
    Video = "VIDEO", 
    BlogPost = "BLOG_POST", 
    Quiz = "QUIZ"
}

Upvotes: 1

Views: 121

Answers (1)

MauriceNino
MauriceNino

Reputation: 6747

Because an enum instance without a declared value is just an incrementing number. If you didn't write strings to it, it would mean something like this:

enum Type{
    Video = 0, 
    BlogPost = 1,
    Quiz = 2
}

Therefore, (if you leave one empty), your enum Type is not of type string, but rather string | number and therefore you are allowed to pass a number OR a string.

Upvotes: 1

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