data-migration-config.ts

import { TypeOrmModuleOptions } from '@nestjs/typeorm';
import * as path from 'path';
import * as dotenv from 'dotenv';
import * as fs from 'fs';

function buildConnectionOptions(filePath: string, env: string | undefined): TypeOrmModuleOptions {
    let data: any = process.env;

    if (fs.existsSync(filePath)) {
        data = { ...data, ...dotenv.parse(fs.readFileSync(filePath)) };
    }

    /* use the database connection URL if available ( Heroku postgres addon uses connection URL ) */
    const connectionParams = process.env.DATABASE_URL
        ? {
            url: process.env.DATABASE_URL,
            ssl: { rejectUnauthorized: false, ca: process.env.CA_CERT },
        }
        : {
            database: data.PG_DB,
            port: +data.PG_PORT || 5432,
            username: data.PG_USER,
            password: data.PG_PASS,
            host: data.PG_HOST,
            connectTimeoutMS: 5000,
            extra: {
                max: 25,
            },
        };

    const entitiesDir =
        process.env.NODE_ENV === 'test' ? [__dirname + '/**/*.entity.ts'] : [__dirname + '/**/*.entity{.js,.ts}'];

    return {
        type: 'postgres',
        ...connectionParams,
        entities: entitiesDir,
        synchronize: false,
        uuidExtension: 'pgcrypto',
        migrationsRun: false,
        migrationsTransactionMode: 'all',
        logging: data.ORM_LOGGING || false,
        migrations: [__dirname + '/data-migrations/**/*{.ts,.js}'],
        keepConnectionAlive: true,
        cli: {
            migrationsDir: 'migrations',
        },
    };
}

function determineFilePathForEnv(env: string | undefined): string {
    if (env === 'test') {
        return path.resolve(process.cwd(), './.env.test');
    } else {
        return path.resolve(process.cwd(), './.env');
    }
}

function fetchConnectionOptions(): TypeOrmModuleOptions {
    const env: string | undefined = process.env.NODE_ENV;
    const filePath: string = determineFilePathForEnv(env);

    return buildConnectionOptions(filePath, env);
}

const ormconfig: TypeOrmModuleOptions = fetchConnectionOptions();
export default ormconfig;