How to use the command 'yarn' (with examples)
Yarn is a JavaScript and Node.js package manager alternative that allows you to efficiently manage dependencies and packages. It provides various commands to perform different tasks such as installing modules, adding dependencies, removing modules, and creating a package.json file. In this article, we will explore different use cases of the ‘yarn’ command along with examples.
Use case 1: Install a module globally
Code:
yarn global add module_name
Motivation: This command installs a module globally, making it accessible across different projects without the need for multiple installations. It is useful when you want to use a module in multiple projects without having to specify it as a dependency or dev dependency in each individual project’s package.json file.
Explanation:
yarn: The yarn command is used to execute yarn commands.global: The global flag specifies that the module should be installed globally.add: The add command is used to add a module.module_name: The name of the module you want to install globally.
Example output:
yarn global add nodemon
This command will install the ’nodemon’ module globally and make it available across all projects.
Use case 2: Install all dependencies referenced in the package.json file
Code:
yarn install
Motivation: This command installs all the dependencies listed in the package.json file. It is essential when you clone a project or want to ensure that all the required dependencies are installed before running the code.
Explanation:
yarn: The yarn command is used to execute yarn commands.install: The install command is used to install all the dependencies.
Example output:
yarn install
This command will install all the dependencies specified in the package.json file of the current project.
Use case 3: Install a module and save it as a dependency to the package.json file
Code:
yarn add module_name@version
Motivation: This command is used to install a module and add it as a dependency to the package.json file. It helps keep track of the project’s dependencies and ensures that other developers who clone the project have access to the same modules.
Explanation:
yarn: The yarn command is used to execute yarn commands.add: The add command is used to add a module.module_name: The name of the module you want to install.version: (Optional) The specific version of the module you want to install. If not specified, the latest version will be installed.
Example output:
yarn add express@^4.17.1
This command will install the ’express’ module with version 4.17.1 and save it as a dependency in the package.json file.
Use case 4: Uninstall a module and remove it from the package.json file
Code:
yarn remove module_name
Motivation: This command is used to uninstall a module and remove it from the package.json file. It helps in managing project dependencies and keeping the package.json file up to date.
Explanation:
yarn: The yarn command is used to execute yarn commands.remove: The remove command is used to uninstall a module.module_name: The name of the module you want to uninstall.
Example output:
yarn remove lodash
This command will uninstall the ’lodash’ module and remove it from the package.json file.
Use case 5: Interactively create a package.json file
Code:
yarn init
Motivation: This command allows you to interactively create a package.json file. It prompts you to provide information about your project, such as the project name, version, description, entry point, author, and more. It is useful when starting a new project and wanting to quickly generate a package.json file with the necessary information.
Explanation:
yarn: The yarn command is used to execute yarn commands.init: The init command is used to interactively create a package.json file.
Example output:
yarn init
This command will start an interactive prompt where you can enter the required information to create a package.json file for your project.
Use case 6: Identify whether a module is a dependency and list other modules that depend upon it
Code:
yarn why module_name
Motivation: This command helps in understanding the dependency tree of your project. It allows you to identify whether a specific module is a dependency and lists other modules that depend upon it. It is useful when you want to analyze the impact of removing a module or to troubleshoot dependency conflicts.
Explanation:
yarn: The yarn command is used to execute yarn commands.why: The why command is used to identify whether a module is a dependency and list other modules that depend upon it.module_name: The name of the module you want to analyze.
Example output:
yarn why axios
This command will display the reasons why the ‘axios’ module is installed (e.g., which direct and transitive dependencies require it) and list other modules that depend upon ‘axios’.
Conclusion:
The ‘yarn’ command provides various functionalities to manage JavaScript and Node.js packages. By exploring the different use cases illustrated in this article, you can efficiently install, uninstall, manage dependencies, and create a package.json file. Understanding these use cases will streamline your development process and ensure the smooth functioning of your projects.
