tweak(db): exists method on database and database model classes

packages/database/src/DatabaseModel.js

@@ -197,6 +197,13 @@ export class DatabaseModel {
     return this.database.count(this.databaseRecord, ...args);
   }
 
+  /**
+   * @returns {Promise<boolean>}
+   */
+  async exists(...args) {
+    return await this.database.exists(this.databaseRecord, ...args);
+  }
+
   async findById(id, customQueryOptions = {}) {
     if (!id) {
       throw new Error(`Cannot search for ${this.databaseRecord} by id without providing an id`);

packages/database/src/TupaiaDatabase.js

@@ -294,6 +294,15 @@ export class TupaiaDatabase {
     return buildQuery(this.connection, ...args);
   }
 
+  /**
+   * @returns {Promise<boolean>}
+   */
+  async exists(...args) {
+    const innerQuery = this.find(...args);
+    const [{ exists }] = await this.executeSql('SELECT EXISTS(?);', [innerQuery]);
+    return exists;
+  }
+
   /**
    *
    * @param {string} recordType