Can the values of an enum in TypeScript be accessed as an array?
For example:
enum MyEnum {
FOO = 'foo',
BAR = 'bar'
}
would become
['foo', 'bar']
Can the values of an enum in TypeScript be accessed as an array?
For example:
enum MyEnum {
FOO = 'foo',
BAR = 'bar'
}
would become
['foo', 'bar']
A feasible approach is to utilize:
Object.values(MyEnum)
due to the fact that after compilation, an enum becomes a JS object:
var MyEnum;
(function (MyEnum) {
MyEnum["FOO"] = "foo";
MyEnum["BAR"] = "bar";
})(MyEnum || (MyEnum = {}));
If you're looking to ensure that your code is fully typed, one approach is to utilize the template literal operator in TypeScript to infer the list of values as a specific type:
enum MyEnum {
FOO = 'foo',
BAR = 'bar'
}
type MyEnumValue = `${MyEnum}`
// Result: type MyEnumValue = "foo" | "bar"
const valuesList: MyEnumValue[] = Object.values(MyEnum)
// Result: ["foo", "bar"]
For further information on dynamically obtaining the values of an enum, check out this reference article. (note: I am the author of the article)
If you're working with a string enum, the easiest method is to utilize the Object.values function
enum MyEnum {
FOO = 'foo',
BAR = 'bar'
}
console.log(Object.values(MyEnum));
Update:
In my opinion, @Fyodor's approach stands out as more efficient as it addresses string enums:
const enumValues = Object.values(MyEnum).filter(val => typeof val === 'string')
This code snippet demonstrates how to handle numeric enums and ensures type checking:
type EnumObject = {[key: string]: number | string};
type EnumObjectEnum<E extends EnumObject> = E extends {[key: string]: infer ET | string} ? ET : never;
function extractEnumValues<E extends EnumObject>(enumObject: E): EnumObjectEnum<E>[] {
return Object.keys(enumObject)
.filter(key => Number.isNaN(Number(key)))
.map(key => enumObject[key] as EnumObjectEnum<E>);
}
For instance:
enum NumEnum {
X,
Y,
Z,
}
// The resultant type will be inferred as NumEnum[]
let numEnumResults = extractEnumValues(NumEnum);
Additional information can be found at: Exploring TypeScript Enum Values
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