Creating a Shared Library in nodejs

how do i create a shared library between npm projects


To create a shared library between NPM projects, you can follow these steps:

Create a new NPM project for your shared library. You can do this by running npm init in a new directory.

Write your library code and export the relevant functions, classes or modules using the module.exports syntax in Node.js or the export syntax in ES6.

Once your library is complete, publish it to the NPM registry using the npm publish command. This will make your library available for installation in other projects.

In your other NPM projects that need to use the shared library, add a dependency to your library in the package.json file. You can do this by running npm install <your-library-name>.

Import your library in your project code using the require syntax in Node.js or the import syntax in ES6.

Use the functions or classes from your shared library in your project code.

Note: You may want to consider versioning your shared library to ensure that changes made to the library do not break dependent projects. You can do this by specifying a version number in your library's package.json file and updating it each time you make a change.





can i share it locally?
  
Yes, you can also share your library locally without publishing it to the NPM registry. Here's how you can do it:

In your shared library project, run the npm pack command. This will create a tarball file of your library in the current directory.

Copy the tarball file to the other project directory where you want to use the shared library.

In the other project directory, run the npm install /path/to/your/tarball/file command. This will install the library as a local dependency in your project.

Import your library in your project code using the require syntax in Node.js or the import syntax in ES6.

Use the functions or classes from your shared library in your project code.

Note: When using a locally installed library, you will need to repeat steps 2-3 each time you make changes to your shared library project. Alternatively, you can set up a symbolic link between your shared library project and your dependent project's node_modules directory, which will allow changes to be automatically reflected in the dependent project. To do this, you can run the npm link command in your shared library project and the npm link <your-library-name> command in your dependent project.





what is a tarball

A tarball is a compressed archive file that contains a collection of files and directories. The name "tarball" is derived from the combination of the terms "tar" and "ball".

The "tar" part refers to the tar archiving utility, which is used to combine multiple files into a single file for easier storage and transportation. The "ball" part refers to the fact that the resulting file is typically compressed, often using gzip or bzip2, to reduce its size.

Tarballs are commonly used for software distribution, as they allow developers to package up their code and any required dependencies into a single file that can be easily installed on other systems. In the case of Node.js, tarballs are often used to distribute NPM packages.

To create a tarball in Node.js, you can use the npm pack command in your package's directory. This will create a compressed archive file with a .tgz extension that contains your package's code and metadata. The resulting tarball can then be published to the NPM registry or shared locally as described in the previous answer.





how do i use the npm link command

The npm link command allows you to create a symbolic link between a locally developed NPM package and another NPM project that you want to use it in. Here are the steps to use the npm link command:

Navigate to the root directory of the NPM package you want to link.

Run the npm link command. This will create a global symbolic link to your package that can be accessed from any directory on your machine.

Navigate to the root directory of the NPM project you want to link the package to.

Run the npm link <your-package-name> command. This will create a local symbolic link to your package in the node_modules directory of the project.

Import the package as you would with any other NPM package in your project code using the require syntax in Node.js or the import syntax in ES6.

Make any necessary changes to your package code and run npm run build or npm run watch to rebuild your package.

The changes you made to your package should now be reflected in your project code.

Note: If you want to unlink the package, you can run the npm unlink command in your package directory and the npm unlink <your-package-name> command in your project directory.

and if i use typescript for the library
If you are using TypeScript for your library, you need to make sure that the TypeScript code is compiled into JavaScript before it can be used in your dependent projects. Here are the steps to build your TypeScript library with the linked package:

In your library project directory, run npm link to create a global link to your library.

In your dependent project directory, run npm link <your-library-name> to create a local link to your library.

In your library project, add a build script to your package.json file that compiles your TypeScript code into JavaScript. For example:

json
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{
  "name": "<your-library-name>",
  "version": "1.0.0",
  "main": "dist/index.js",
  "scripts": {
    "build": "tsc"
  },
  "devDependencies": {
    "typescript": "^4.0.0"
  }
}
Run npm install in your library project directory to install the TypeScript compiler.

Write your TypeScript code in the src/ directory of your library project.

When you are ready to build your library, run npm run build in your library project directory. This will compile your TypeScript code into JavaScript and output the resulting files in the dist/ directory.

In your dependent project, import the library using the require syntax in Node.js or the import syntax in ES6. Make sure to reference the compiled JavaScript file in the dist/ directory, not the TypeScript file in the src/ directory. For example:

javascript
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const myLibrary = require('<your-library-name>').default;
// or
import myLibrary from '<your-library-name>';
Make any necessary changes to your library code and repeat steps 6-7 to rebuild and update your dependent project with the latest changes.
Note: If you are using a bundler like Webpack or Rollup to build your dependent project, make sure to configure it to handle the TypeScript code and the linked library correctly.




Matteo L
and if my project is written in typescript
If your dependent project is also written in TypeScript, you can use the tsconfig.json configuration file to reference the TypeScript code in your linked library directly.

Here are the steps to use a linked TypeScript library in your TypeScript project:

In your library project directory, run npm link to create a global link to your library.

In your dependent project directory, run npm link <your-library-name> to create a local link to your library.

In your dependent project, make sure that the tsconfig.json file references the TypeScript code in your linked library. For example, you can add a paths section to your tsconfig.json file like this:

json
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{
  "compilerOptions": {
    "baseUrl": "./src",
    "paths": {
      "<your-library-name>/*": ["../<your-library-name>/src/*"]
    }
  },
  "include": [
    "src/**/*"
  ]
}
In your dependent project, import the library using the import syntax in TypeScript. TypeScript will automatically find and use the linked package. For example:
javascript
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import myLibrary from '<your-library-name>';
Make any necessary changes to your library code and rebuild your dependent project with tsc or your TypeScript build tool of choice.
Note: If you are using a bundler like Webpack or Rollup to build your dependent project, make sure to configure it to handle the linked library correctly. You may need to add the linked library to the externals section of your webpack config, for example.