How to use the command 'fnm' (with examples)

Fast Node Manager (fnm) is a powerful tool for developers working with Node.js, offering an efficient way to manage and switch between different versions of Node.js. This versatility is crucial for development environments where projects may depend on different Node.js versions. With fnm, users can effortlessly install, switch, and manage multiple Node.js versions to match their project’s requirements and ensure compatibility and performance.

Install a specific version of Node.js

Code:

fnm install node_version

Motivation: Installing a specific version of Node.js is often necessary when working on projects that depend on particular Node.js features or APIs that are available only in certain versions. Using fnm, developers can ensure they have the exact version required without disrupting other projects or system configurations.

Explanation:

• install: This command directs fnm to fetch and install the specified version of Node.js.
• node_version: Replace this placeholder with the specific Node.js version you wish to install, such as 14.17.3 or 16.6.1.

Example Output:

Downloading and installing node v14.17.3...
Node v14.17.3 installed successfully.

List all available Node.js versions and highlight the default one

Code:

fnm list

Motivation: Listing all installed Node.js versions is particularly useful when you need to assess what versions are currently available on your machine. It helps in comparing compatibility between projects and making informed decisions about version upgrades or downgrades. Additionally, this command highlights which version is set as the default, ensuring clarity on what version is currently being used globally.

Explanation:

• list: This simple command shows a list of all Node.js versions installed through fnm. It provides an organized view of version management on your system.

Example Output:

v12.22.1
v14.17.3
v16.6.1 (default)

Use a specific version of Node.js in the current shell

Code:

fnm use node_version

Motivation: Sometimes, a project may require a specific Node.js version to run properly. The fnm use command allows developers to temporarily switch to a different Node.js version for a session, ensuring that any commands executed in the current shell will utilize the specified Node.js version without changing the default system-wide version.

Explanation:

• use: This command instructs fnm to switch the active Node.js version to the one specified for the current shell session.
• node_version: This is the version of Node.js you wish to use temporarily within your shell, like 12.22.1.

Example Output:

Now using node v12.22.1

Set the default Node.js version

Code:

fnm default node_version

Motivation: Setting a default Node.js version is essential for ensuring consistency in environments where multiple applications or services rely on Node.js. By setting a default version, you specify which Node.js version should be used globally across your system unless another version is specified in a particular session.

Explanation:

• default: This command sets the specified version as the default for all shell sessions, ensuring that all general Node.js executions will utilize this version going forward.
• node_version: The Node.js version you want to set as the default, such as 16.6.1.

Example Output:

Default node version set to v16.6.1

Uninstall a given Node.js version

Code:

fnm uninstall node_version

Motivation: Over time, as projects evolve and the Node.js ecosystem updates, certain Node.js versions may become obsolete or no longer necessary for development. Uninstalling unused Node.js versions with fnm helps conserve disk space and declutters the available list of Node.js versions, making version management simpler and more efficient.

Explanation:

• uninstall: This command removes the specified version of Node.js from your system.
• node_version: The Node.js version you want to uninstall, for example, 14.17.3.

Example Output:

Uninstalling node v14.17.3...
Node v14.17.3 has been successfully uninstalled.

Conclusion:

Incorporating fnm into your development workflow offers significant benefits in terms of managing Node.js versions with ease and efficiency. Whether it is maintaining version-specific projects, toggling between versions for testing, or keeping your system clean and organized, fnm provides the necessary commands and flexibility to meet your Node.js version management needs. By understanding these use cases, developers can harness the full potential of fnm in their software development processes.