promised-websql/lib/index.js

  # Promised WebSQL

export default function PromisedSQLite(db) {

  if (!is_valid_db(db)) {
    throw new Error('Expected a valid DB object. ');
  }

  return {
    sql: do_sql(db),
    sqls: do_sqls(db),
  };
}

const do_sql = (db) => (sql_query, parameters) => {
  if (!is_valid_sql_query(sql_query)) {
    throw new Error('Expected a valid SQL query');
  }
  if (!are_valid_sql_parameters(parameters)) {
    throw new Error('Expected valid SQL parameters')
  }
  return new Promise((resolve, reject) =>
    db.transaction((tx) =>
        tx.executeSql(
          sql_query,
          parameters,
          (transaction, resultSet) => resolve([transaction, resultSet]),
          (transaction, error) => reject([transaction, error])
        ),
      (error) => reject([sql_query, error])
    )
  )
};

const do_sqls = (db) => (sql_queries) => {
  if (!are_valid_sql_queries(sql_queries)) {
    throw new Error('Expected valid SQL queries');
  }
  return new Promise((resolve, reject) =>
    db.transaction((tx) =>
        Promise.all(sql_queries.map(([sql_query, ...parameters]) => {
          if (!is_valid_sql_query(sql_query)) {
            reject([sql_query, 'Expected valid SQL query']);
          }
          if (!are_valid_sql_parameters(parameters)) {
            console.log(parameters);
            reject([sql_query, 'Expected valid parameters']);
          }
          return new Promise((inner_resolve, inner_reject) =>
            tx.executeSql(
              sql_query,
              parameters,
              (transaction, resultSet) => inner_resolve([transaction, resultSet]),
              (transaction, error) => inner_reject([transaction, error])
            )
          );
        })).then(resolve).catch(reject),
      (error) => ([sql_queries, error])
    )
  );
};

const is_valid_db = (db) =>
  db !== null &&
  typeof db === 'object' &&
  typeof db.transaction === 'function';

const is_valid_sql_query = (sql_query) =>
  sql_query !== null &&
  typeof sql_query === 'string' &&
  sql_query.length > 0;

const are_valid_sql_parameters = (parameters) =>
  !parameters ||
  (Array.isArray(parameters) && parameters.every((parameter) => typeof parameter === 'string'));

const are_valid_sql_queries = (queries) =>
  queries &&
  Array.isArray(queries) &&
  queries.length > 0 &&
  queries.every((query) =>
    Array.isArray(query) &&
    query.length > 0 &&
    query.every(([sql, ...params]) =>
      is_valid_sql_query(sql) && are_valid_sql_parameters(params)));