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

Nx is a powerful command-line interface used to manage workspaces efficiently within monorepos. It’s designed for modern frontend development and supports a wide range of tools including Angular, React, and Node.js. Nx simplifies the management of codebases, encourages code reusability, and optimizes the execution of development commands, making it a valuable tool for developers working in large-scale projects.

Use case 1: Build a specific project

Code:

nx build project

Motivation:

When working within a monorepo, you might have several projects or applications. At times, you need to build a specific project for testing or deployment purposes without running the build process on the entire workspace. Building individual projects streamlines the continuous integration process and reduces the overhead time involved.

Explanation:

• nx: This initiates the Nx command-line interface.
• build: This refers to the action of compiling the project’s source code.
• project: This is the name or identifier of the specific project you intend to build within your workspace.

Example output:

> nx run project:build 
Starting build process for the project...
✔  Successfully built the project.

Use case 2: Test a specific project

Code:

nx test project

Motivation:

Testing is a critical part of the development process to ensure reliability and functionality. Running tests on a specific project helps isolate issues and verify the integrity of the code before merging or deploying changes, thereby maintaining code quality across different projects.

Explanation:

• nx: Invokes the Nx CLI.
• test: Specifies the testing operation, which generally executes unit and integration tests.
• project: The target project upon which you want to run the tests.

Example output:

> nx run project:test
Running tests for the project...
✔  All tests passed successfully.

Use case 3: Execute a target on a specific project

Code:

nx run project:target

Motivation:

Developers often need to perform specific tasks like linting, serving, or custom scripts on individual projects. This command allows executing any defined custom target, such as lint or serve, on a specific project, which is useful for customization and automation processes.

Explanation:

• nx: Starts the Nx CLI utility.
• run: Command to execute a particular task/target.
• project:target: Denotes the project and the specific target task to be executed.

Example output:

> nx run project:target
Executing 'target' for project...
✔  Target completed successfully.

Use case 4: Execute a target on multiple projects

Code:

nx run-many --target target --projects project1,project2

Motivation:

Managing and synchronizing changes across multiple projects in a monorepo can be challenging. This command allows developers to consistently apply the same target, like build or test, across multiple specified projects, facilitating simultaneous updates and efficiency.

Explanation:

• nx: The foundational Nx command.
• run-many: Enables executing a command on multiple projects at once.
• --target target: Defines the specific target task to perform.
• --projects project1,project2: Specifies the projects on which to run the target separated by commas.

Example output:

> nx run-many --target target --projects project1,project2
Executing 'target' on project1...
✔  Project1 'target' completed.
Executing 'target' on project2...
✔  Project2 'target' completed.

Use case 5: Execute a target on all projects in the workspace

Code:

nx run-many --target target --all

Motivation:

In environments where all projects need a uniform change or update, running a specific command across all projects in the workspace ensures consistency and reduces manual effort. This is especially practical for global updates like running all project tests before a major release.

Explanation:

• nx: The command-line interface indicator for Nx.
• run-many: Command for executing an operation across several projects.
• --target target: Represents the specific task or command to be executed.
• --all: Flags all projects within the workspace without specifying them individually.

Example output:

> nx run-many --target target --all
Executing 'target' for all projects...
✔  All projects completed 'target' successfully.

Use case 6: Execute a target only on projects that have been changed

Code:

nx affected --target target

Motivation:

In large workspaces, it’s inefficient to run tasks on all projects when only a few have changed. The affected command targets only those projects with modifications, optimizing time and computational resources during the development process.

Explanation:

• nx: The beginning step using the Nx CLI.
• affected: Targets only projects that are marked by changes.
• --target target: Specifies the particular command to execute on affected projects.

Example output:

> nx affected --target target
Identifying affected projects...
Executing 'target' on affected projects...
✔  Completed 'target' on affected projects.

Conclusion:

Nx provides a comprehensive command-line toolset to manage multiple projects within a monorepo, ensuring efficient workflows and streamlined processes. With its range of commands and flexibility, Nx helps developers simplify tasks such as building, testing, and executing operations across different sections of a project, ultimately improving productivity and maintaining code quality.