Is there a way in javascript to avoid repeating the same variable in a logic expression?

Question

For example, instead of:

if (ext === "_st" || ext ==="_mt" || ext === "_00" ){
   //do something
}

I would intuitively expect that the following also works:

if (ext === ("_st" || "_mt" || "_00" )){
    //do something
}

But that doesn't work. Is there a way to avoid repeating the same ("ext" in this case) variable for more compressed and efficient code?

UPDATE: I did a search before asking and none of the "duplicate" questions appeared in the first 10-15 suggestions. Instead, StackOverflow made WRONG suggestions for irrelevant -false duplicates.

Here is my suggestion: Instead of marking questions as "duplicate" why not merge them along with the answers in one single question with an intuitive title?

Thanks for the answers.

UPDATE #2: This is NOT a duplicate. The suggested questions have answers that only refer to OR optimization while my question is more general, it refers to "logic expressions", NOT specifically to OR. I just provided an OR example. I'm specifically asking whether there is a method to avoid repeating the main variable in a logical statement whether it is OR, AND, etc.

For example: given var1 == var2 == var3

if (ext === var1 && ext === var2 && ext === var3 ){
   //do something
}

Answer 1

var ext = "_00";
if (/^_st$|^_mt$|^_00$/.test(ext) ){
    console.log("do something");
   //do something
}

Using regex this is possible.

Explanation: Each comparison is separated by an |(or) and enclosed in ^ and $ to match exactly otherwise it would match else where.

Answer 2

let ext = "_mt";

if( ext.match( /_st|_mt|_00/g ) ) {
  console.log("Yes : type 1");
}


if( ["_st", "_mt", "_00"].includes( ext ) ) {
  console.log("Yes : type 2");
}

As @Shily said you can use an array and this kind of regex too