Obtaining an index from matching variables

[tribal mason]

I have an array that looks something similar to this:
["A", "B", "C", "D", "E", "F"]
These strings are all potential tags that a player will have. With the way the map is set up, you're only going to have one of these tags at a time.

I want to be able to find the index that has the matching tag as the player being checked, and then obtain the index number from there.

For example, if the matching tags were "C", I should get the value of 2.

I've considered a scoreboard or something as a workaround, but not only am I a full year into this map so I don't want to go back and fix all that (inb4 sunk-cost fallacy statement), but this is also an opportunity to learn more about what I can do with arrays since I'm still a noob with them.

[copper hollow]

I'm not very good at this either, but assuming the player only has one of the tags in the array I think this should work

const array = ["A", "B", "C", "D", "E", "F"];
let value;

array.forEach((e) => {
    if(!player.hasTag(e)) return;
    value = array.indexOf(e);
})

[past moon]

Probably the easiest way to do this

const tags = ["A", "B", "C", "D", "E", "F"]

tags.findIndex(tag => player.hasTag(tag))

[harsh orbit]

If you still want to use tags.forEach() the index is returned as a second variable. https://www.w3schools.com/jsref/jsref_foreach.asp