How to migrate from lerna to pnpm

Migrating from Lerna to pnpm is a process that involves restructuring the project management structure, optimizing dependency management, and improving workflow processes. Here are the detailed and organized steps for the migration process, with an example to illustrate.

Step 1: Evaluate the existing Lerna project structure

Before starting the migration, it's important to conduct a comprehensive evaluation of the current Lerna project. This includes understanding the dependencies between all packages, the build process, and the release process.

Example: Suppose we have a monorepo managed by Lerna that includes three packages: package-a, package-b, and package-c. package-a and package-b both depend on package-c.

Step 2: Install and configure pnpm

After confirming the project structure and dependencies, the next step is to install pnpm. pnpm can be installed using npm:

bash
npm install -g pnpm

Then, to use pnpm in the monorepo, we need to create a pnpm-workspace.yaml file to define the workspace settings.

Example: Create a pnpm-workspace.yaml file in the project root directory with the following contents:

yaml
packages:
  - 'packages/*'

Step 3: Migrate dependency management for each package

Switch dependency management for each package's package.json from Lerna to pnpm. This includes using pnpm commands to install dependencies and ensuring that all internal dependencies are correctly set up using pnpm's linking method.

Example: For package-a, if it depends on package-c, specify the dependency in package-a's package.json using pnpm:

json
"dependencies": {
  "package-c": "workspace:^1.0.0"
}

Step 4: Adjust CI/CD scripts

During the migration process, make sure to update the scripts for continuous integration and deployment to use pnpm commands and configurations. This may involve modifying build scripts, test scripts, and deployment scripts.

Example: In the CI configuration file, replace npm or yarn commands with pnpm commands:

yaml
build:
  script:
    - pnpm install
    - pnpm run build

Step 5: Verify and test the migration

After completing the above steps, conduct comprehensive testing to ensure that all packages can correctly install dependencies, build, and run. This may include unit testing, integration testing, and end-to-end testing.

Example: Run pnpm commands to verify that installation and building were successful:

bash
pnpm install
pnpm run build

Step 6: Cleanup and optimize after migration

After the migration is complete, it may be necessary to clean up the project, such as deleting unnecessary Lerna configuration files and optimizing the new pnpm configuration.

By following these steps, we can successfully migrate from Lerna to pnpm, improving efficiency in dependency management and optimizing the entire project's build and release processes. We hope this example helps you understand the specific steps and considerations for migration.

Lerna is a tool used to manage JavaScript projects with multiple packages, which can optimize workflows that are difficult to handle using git and npm. However, LeRNA does not directly handle package dependencies, but rather needs to be used in conjunction with package managers such as NPM or Yarn.

Pnpm is a space saving package manager. It saves disk space through hard linking and symbolic linking, and can provide native support for multi package (monorepo) projects. This means that we can use only pnpm to achieve the same effect when using Lenna in combination with npm or yarn.

The migration from Lerna to pnpm can be roughly divided into the following steps:

1. Evaluate project requirements

Firstly, we should evaluate the existing LeRNA project structure and dependencies to determine if all functions can be found to be equivalently implemented in pnpm. This includes:

-Multi package version synchronization -Handling dependencies between packages -Release process -Custom Script

2. Install PNPM

Next, we need to install pnpm in the development environment, which can usually be done through the following command:

sh
npm install -g pnpm

3. Initialize PNPM workspace

Create a 'pnpm workspace. yaml' file using the following command, which will define the settings for the workspace:

sh
pnpm init

Then edit this file and add a configuration similar to the following, specifying the location of the package:

yaml
packages:
- 'packages/*'

4. Adjust the 'package. json' file

Add the workspace configuration for 'pnpm' to the 'package. json' file in the root directory of the project:

json
{
"private": true,
"workspaces": [
"packages/*"
]
}

5. Remove Lerna configuration

You can remove the configuration file 'lerna. json' for Lerna and ensure that the relevant Lerna commands are removed from the script section of 'package. json'.

6. Migration scripts and commands

If there are scripts that use Lenna for package management (such as Lenna bootstrap), these scripts need to be modified to the corresponding command of pnpm. For example, 'lerna bootstrap' can be replaced by 'pnpm install' because pnpm automatically links packages in the workspace.

7. test

After completing the configuration, it is necessary to thoroughly test the entire project to ensure that all dependencies are installed correctly, the script can run normally, and the CI/CD process is not affected.

8. Update documentation and continuous integration configuration

Don't forget to update the project documentation to reflect new build steps and commands, while ensuring that the CI/CD system uses pnpm to install dependencies and execute tasks.

Example

Suppose we have a project managed by LeRNA that includes two packages: 'package-a' and 'package-b', where 'package-b' depends on 'package-a'.

In Lenna, we may have a 'lerna. json' file in the root directory of the project, which contains the following content:

json
{
"packages": ["packages/*"],
"version": "independent"
}

We will also see similar 'scripts' in the' package. json 'file:

json
{
"scripts": {
"bootstrap": "lerna bootstrap",
"publish": "lerna publish"
}
}

After migrating to PNPM, we no longer need this' lerna. json 'file, but instead add workspace configuration in the' package. json 'root directory and update the script:

json
{
"private": true,
"workspaces": ["packages/*"],
"scripts": {
"install": "pnpm install",
"publish": "pnpm publish --filter ./packages/*"
}
}

In this way, we have completed the basic migration process from Lerna to pnpm. Of course, the migration of specific projects may be more complex, requiring gradual completion and ensuring that each step is executed correctly.