List of Strings:
const myStrings = ["one", "two", "three"];
const newString = "two";
The variable newString is currently just a string, but I would like its type to be an element of myStrings.
Is there a way to achieve this even if the values in the array are subject to change?
To confirm the data type of an element within myStrings, it is essential to declare myStrings using as const in TypeScript to signify its immutability:
const myStrings = ["one", "two", "three"] as const;
type MyStringsElement = typeof myStrings[number]; // For easier reference
const newString: MyStringsElement = "two";
Take a look at the example on playground
Considering the values provided in myStrings, the type of newString will be a combination of string literals:
"one" | "two" | "three""one", "two', or "three" can be assigned to newString (as constant values during compilation).
(Please take note: When utilizing typeof myStrings[number], TypeScript interprets it as (typeof myStrings)[number].)
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