Error running generated migration

Describe the bug I use the CLI command to generate a migration (npx mikro-orm migration:create), and when I try to run the migration (npx mikro-orm migration:up) I get: TypeError: Class constructor Migration cannot be invoked without ‘new’

Stack trace

[Nest] 65039   - 01/09/2020, 6:16:32 PM   [MikroORM] == Migration20200109161524: migrating =======
mikro-orm migration:up

Migrate up to the latest version

Options:
  -t, --to       Migrate up to specific version                         [string]
  -f, --from     Start migration from specific version                  [string]
  -o, --only     Migrate only specified versions                        [string]
  -v, --version  Show version number                                   [boolean]
  -h, --help     Show help                                             [boolean]

TypeError: Class constructor Migration cannot be invoked without 'new'
    at new Migration20200109161524 (/Users/.../app/backend/src/migrations/Migration20200109161524.ts:56:42)
    at Migrator.resolve (/Users/.../app/node_modules/mikro-orm/dist/migrations/Migrator.js:67:26)
    at Object.customResolver (/Users/.../app/node_modules/mikro-orm/dist/migrations/Migrator.js:26:46)
    at Migration.migration (/Users/.../app/node_modules/umzug/lib/migration.js:63:38)
    at /Users/.../app/node_modules/umzug/lib/migration.js:123:37
    at Generator.next (<anonymous>)
    at step (/Users/.../app/node_modules/babel-runtime/helpers/asyncToGenerator.js:17:30)
    at /Users/.../app/node_modules/babel-runtime/helpers/asyncToGenerator.js:35:14
    at new Promise (<anonymous>)
    at new F (/Users/.../app/node_modules/babel-runtime/node_modules/core-js/library/modules/_export.js:36:28)
    at /Users/.../app/node_modules/babel-runtime/helpers/asyncToGenerator.js:14:12
    at Migration._exec (/Users/.../app/node_modules/umzug/lib/migration.js:136:7)
    at Migration.up (/Users/.../app/node_modules/umzug/lib/migration.js:90:17)
    at Umzug.<anonymous> (/Users/.../app/node_modules/umzug/lib/index.js:152:22)
    at PassThroughHandlerContext.finallyHandler (/Users/.../app/node_modules/bluebird/js/release/finally.js:57:23)
    at PassThroughHandlerContext.tryCatcher (/Users/.../app/node_modules/bluebird/js/release/util.js:16:23)

To Reproduce Steps to reproduce the behavior:

1. npx mikro-orm migration:create
2. npx mikro-orm migration:up

Expected behavior Run the migration

Additional context

• npx mikro-orm schema:create --run works without issues, which makes me believe that the configuration is OK, regardless of the complex project structure
• mikro-orm is used with NestJS using nestjs-mikro-orm, as used in the sample project
• SQL code for the migration is OK
• Replacing SQL code with “SELECT 1+1” results to the same issue

Versions

Dependency	Version
node	12.13.1
typescript	3.7.4
mikro-orm	3.0.0-rc.5
pg	7.17.0

[onadebi]

So, this might be useful to someone who comes across this. The short answer for me that resolved this issue was setting target property of my tsconfig.json file, to “ESNEXT”

[B4nan]

In next RC version you should be able to provide the path to tsconfig via tsConfigPath in your package.json.