@eunmo/mysql

An async wrapper for MySQL connection pool. This package tries to hide away the boilerplates for the MySQL library to minimize setup.

Usage

const { dml, query, queryOne } = require('@eunmo/mysql');
awiat dml('CREATE TABLE some_table (C1 int)');
const added1 = await dml('INSERT INTO some_table VALUES (1);');
const added2 = await dml('INSERT INTO some_table VALUES (?);', 2);
const added3 = await dml('INSERT INTO some_table VALUES ?;', [[[3], [4]]]);
const rows = await query('SELECT * FROM some_table;');
const row1 = await queryOne('SELECT * FROM some_table WHERE C1 = ?;', 1);
const row1 = await queryOne('SELECT * FROM some_table WHERE C1 = ?;', [1]);

The return type of dml/query is identical to that of mysql package's connection.query. The return type of queryOne is a single row of mysql package's connection.query or null if no row can be fetched.

Database connection configuration

This package uses the config config package for setup. For starters, put the following in config/default.json.

{
  "dbConfig": {
    "host": "localhost",
    "user": "dummy_user",
    "password": "dummy_password",
    "database": "dummy"
  }
}

If you also want to change the connection pool size, you can also specify it. The default value is 10.

{
  "dbConfig": {
    "host": "localhost",
    "user": "dummy_user",
    "password": "dummy_password",
    "database": "dummy",
    "connectionLimit": 100
  }
}

Jest setup

To use a different config when running jest tests, the following three steps are required.

1. Write the new setup file.

Contents of NODE_CONFIG will be merged with the base config, so only the diff that needs to be changed can be designated. I put this code as server/setup-tests.js.

process.env.NODE_CONFIG = '{"dbConfig":{"database":"dummy_test"}}'

2. Create a jest config file.

This file will point to the setup file from step 1. I put this code as server/jest-config.json.

{
  "setupFiles": ["<rootDir>/setup-tests.js"]
}

3. Run jest with the config file from step 2.

jest server --config server/jest-config.json

Or as part of npm script, run npm run jest with the following in package.json.

{
  "scripts": {
    "jest": "jest server --config server/jest-config.json"
  }
}

Note that if the root directory for jest changes, the path in step 2 should also be updated.

Cleanup per test file

When running tests with jest, the connection pool gets created for every test file. So the connection pool needs to be manually closed. Example:

const { cleanup } = require('@eunmo/mysql');

afterAll(async () => {
  await cleanup();
});