@typeorm/codemod

Automated code migration tool for TypeORM version upgrades.

Usage

# Run all v1 transforms
npx @typeorm/codemod v1 src/

# Dry run (preview changes without writing)
npx @typeorm/codemod v1 --dry src/

# Run a specific transform
npx @typeorm/codemod v1 --transform connection-to-datasource src/

# Exclude files by glob pattern (repeatable)
npx @typeorm/codemod v1 --ignore '**/generated*' --ignore '**/e2e/**' src/

# Control parallelism
npx @typeorm/codemod v1 --workers 4 src/

# List available transforms
npx @typeorm/codemod v1 --list

Options

| Option | Short | Description | | -------------------- | ----- | --------------------------------------------------------------------- | | --dry | -d | Dry run (show changes without writing) | | --help | -h | Show help | | --ignore <pattern> | -i | Additional glob pattern to exclude (repeatable; merged with defaults) | | --list | -l | List available transforms | | --transform <name> | -t | Run a specific transform only | | --version | -v | Print the installed @typeorm/codemod version | | --workers <num> | -w | Number of worker processes (default: CPU cores - 1) |

**/*.d.ts is always excluded — ambient type declarations describe the shapes consumers rely on, and rewriting identifiers inside them would silently corrupt published types. User-provided --ignore patterns are merged on top of this default.

After running

Some transforms leave TODO comments in your code where manual changes are needed. After the codemod completes, it will list all files that require manual review.

Formatting

The codemod uses an AST-based approach which may introduce minor formatting differences (e.g. extra parentheses, quote style changes). Run your project's formatter after the codemod to restore your code style:

npx @typeorm/codemod v1 src/
npx prettier --write src/        # or: npx eslint --fix src/

Scoping

Transforms that rename properties or methods (e.g. .connection to .dataSource) identify TypeORM instances through type annotations. They also recognize untyped class fields whose initializer is a known accessor chain (e.g. private manager = this.dataSource.manager). Code with no typing signal at all may not be transformed automatically — review git diff after running.

Documentation

See the full upgrading guide for details on all breaking changes:

• v1