UserPreferences: simplify DELETE queries (getodk#1427)

Also use existing return value from postgres wire protocol instead of generating an extra value.

Author: alxndrsn

lib/model/query/user-preferences.js

@@ -8,7 +8,7 @@
 // except according to the terms contained in the LICENSE file.
 
 const { sql } = require('slonik');
-
+const Option = require('../../util/option');
 
 const getForUser = (userId) => ({ one }) =>
   one(sql`
@@ -87,37 +87,23 @@ const _writeProperty = (tablename, subject, userId, propertyName, propertyValue)
   `);
 };
 
-
-const _removeProperty = (tablename, subject, userId, propertyName) => ({ maybeOne }) => {
-  const targetColumns = ['userId', 'propertyName']
-    .concat((subject === null) ? [] : ['projectId'])
-    .map(el => sql.identifier([el]));
-
-  const values = [userId, propertyName]
-    .concat((subject === null) ? [] : [subject]);
-
-  return maybeOne(sql`
-    DELETE FROM ${sql.identifier([tablename])}
-    WHERE
-      (${sql.join(targetColumns, `, `)})
-      =
-      (${sql.join(values, `, `)})
-    RETURNING
-      1 AS "deleted_count"
-  `);
-};
-
-
 const writeSiteProperty = (userId, propertyName, propertyValue) => ({ one }) =>
   _writeProperty('user_site_preferences', null, userId, propertyName, propertyValue)({ one });
 
-const removeSiteProperty = (userId, propertyName) => ({ maybeOne }) =>
-  _removeProperty('user_site_preferences', null, userId, propertyName)({ maybeOne });
-
 const writeProjectProperty = (userId, projectId, propertyName, propertyValue) => ({ one }) =>
   _writeProperty('user_project_preferences', projectId, userId, propertyName, propertyValue)({ one });
 
-const removeProjectProperty = (userId, projectId, propertyName) => ({ maybeOne }) =>
-  _removeProperty('user_project_preferences', projectId, userId, propertyName)({ maybeOne });
+const removeSiteProperty = (userId, propertyName) => ({ db }) => db.query(sql`
+  DELETE FROM user_site_preferences
+    WHERE "userId" = ${userId}
+      AND "propertyName" = ${propertyName}
+`).then(({ rowCount }) => Option.of(rowCount || null));
+
+const removeProjectProperty = (userId, projectId, propertyName) => async ({ db }) => db.query(sql`
+  DELETE FROM user_project_preferences
+    WHERE "userId" = ${userId}
+      AND "propertyName" = ${propertyName}
+      AND "projectId" = ${projectId}
+`).then(({ rowCount }) => Option.of(rowCount || null));
 
 module.exports = { removeSiteProperty, writeSiteProperty, writeProjectProperty, removeProjectProperty, getForUser };