Improve isValid for strings

Author: SeanReece

src/objectid.ts

@@ -112,7 +112,7 @@ export class ObjectId extends BSONValue {
       // If intstanceof matches we can escape calling ensure buffer in Node.js environments
       this.buffer = ByteUtils.toLocalBufferType(workingId);
     } else if (typeof workingId === 'string') {
-      if (workingId.length === 24 && checkForHexRegExp.test(workingId)) {
+      if (ObjectId.validateHexString(workingId)) {
         this.buffer = ByteUtils.fromHex(workingId);
       } else {
         throw new BSONError(
@@ -143,6 +143,15 @@ export class ObjectId extends BSONValue {
     }
   }
 
+  /**
+   * @internal
+   * Validates the input string is a valid hex representation of an ObjectId.
+   */
+  private static validateHexString(input: string): boolean {
+    if (input == null || input.length !== 24) return false;
+    return checkForHexRegExp.test(input);
+  }
+
   /** Returns the ObjectId id as a 24 lowercase character hex string representation */
   toHexString(): string {
     if (ObjectId.cacheHexString && this.__id) {
@@ -329,6 +338,7 @@ export class ObjectId extends BSONValue {
    */
   static isValid(id: string | number | ObjectId | ObjectIdLike | Uint8Array): boolean {
     if (id == null) return false;
+    if (typeof id === 'string') return ObjectId.validateHexString(id);
 
     try {
       new ObjectId(id);