Improve performance of isValidTid

.changeset/fast-points-walk.md

@@ -0,0 +1,5 @@
+---
+"@atproto/syntax": patch
+---
+
+Improve performance of isValidTid

packages/syntax/src/tid.ts

@@ -1,24 +1,18 @@
+const TID_LENGTH = 13
+const TID_REGEX = /^[234567abcdefghij][234567abcdefghijklmnopqrstuvwxyz]{12}$/
+
 export const ensureValidTid = (tid: string): void => {
   if (tid.length !== 13) {
     throw new InvalidTidError('TID must be 13 characters')
   }
   // simple regex to enforce most constraints via just regex and length.
-  if (!/^[234567abcdefghij][234567abcdefghijklmnopqrstuvwxyz]{12}$/.test(tid)) {
+  if (!TID_REGEX.test(tid)) {
     throw new InvalidTidError('TID syntax not valid (regex)')
   }
 }
 
 export const isValidTid = (tid: string): boolean => {
-  try {
-    ensureValidTid(tid)
-  } catch (err) {
-    if (err instanceof InvalidTidError) {
-      return false
-    }
-    throw err
-  }
-
-  return true
+  return tid.length === TID_LENGTH && TID_REGEX.test(tid)
 }
 
 export class InvalidTidError extends Error {}