npm install-test Command

Among the multitude of commands that npm offers, the npm install-test command provides an efficient way to install dependencies and immediately run tests. In this article, we'll explore the npm install-test command in detail, including its configuration options, usage scenarios, and practical benefits.

In a typical Node.js project, developers often need to install dependencies and ensure that the code works as expected by running automated tests. The npm install-test command is a shortcut that combines two essential steps—installing packages and running tests—into one seamless command. This saves time and ensures that the installed packages work correctly out of the box.

Understanding npm install-test

The npm install-test command essentially runs an npm install followed by an npm test. It allows developers to install all dependencies listed in the package.json file and then execute the tests defined in the project’s scripts. This command is also useful when you are working with continuous integration (CI) pipelines or automated testing environments, where both installation and testing are required in one operation.

Alias:

The command has a shorthand alias: npm it. This alias functions identically to npm install-test and is a convenient shortcut for developers who prefer concise commands.

Basic Command Structure:

npm install-test [<package-spec> ...]

The package-spec refers to the optional argument that allows you to specify particular packages to install and test against. However, when no arguments are given, npm installs the dependencies from the package.json file.

Command Syntax and Usage

The syntax for the npm install-test command is straightforward and follows the same argument structure as npm install. This means any option or argument you can pass to npm install can also be applied to npm install-test.

Basic Usage:

npm install-test

This will install all the dependencies specified in your package.json file and immediately run the test script defined in the file.

Usage with Specific Package:

npm install-test lodash

This installs the lodash package and then runs the test script, ensuring the newly installed package doesn't break existing functionality.

Key Configuration Options

save

The save option determines whether or not npm saves installed packages to the package.json file as dependencies. By default, npm install-test will save installed packages unless you are using npm update, where it defaults to false.

• Default: true
• Type: Boolean

npm install-test lodash --save

save-exact

This option controls whether npm saves dependencies to package.json with an exact version or with the semver range operator (^, ~). Setting it to true ensures that npm saves the exact version number of the installed package.

• Default: false
• Type: Boolean

npm install-test lodash --save-exact

global

The global option installs packages globally, meaning they are available system-wide rather than just in the local project folder. When running npm install-test with --global, the package will be installed globally, and the test will still run.

• Default: false
• Type: Boolean

npm install-test --global

omit

The omit option allows you to specify which types of dependencies to exclude during installation. For instance, in a production environment, you may want to omit development dependencies to keep your environment lightweight.

• Default: 'dev' if NODE_ENV is set to production; otherwise empty.
• Type: String ("dev", "optional", "peer", can be set multiple times)

npm install-test --omit=dev

strict-peer-deps

When strict-peer-deps is enabled, npm will fail to install if there are any unresolved peer dependencies conflicts. This option helps ensure that your project adheres strictly to the peer dependency rules defined by your packages.

• Default: false
• Type: Boolean

npm install-test --strict-peer-deps

Examples

Example 1: Running npm install-test in a New Project

Suppose you have just cloned a Node.js project from a repository and you want to install its dependencies and run the tests:

git clone https://github.com/example/repo.git
cd repo
npm install-test

This installs all dependencies listed in package.json and runs the test script to ensure everything is functioning correctly.

Example 2: Testing Specific Dependencies After Installation

If you’re working on a project and want to install a specific package and ensure that your tests still pass, you can do the following:

npm install-test express

This will install express, a popular Node.js framework, and then run your project’s test suite to verify that the new package doesn’t introduce any issues.

Example 3: Global Package Installation and Testing

You can install packages globally using npm install-test to ensure that the system-wide installation doesn’t conflict with your local setup:

npm install-test nodemon --global

Use Cases for npm install-test

• CI/CD Pipelines: In continuous integration and continuous deployment (CI/CD) environments, it’s crucial to ensure that the installed dependencies work as expected. Running npm install-test automates this process by installing packages and immediately running tests.
• Testing New Dependencies: When adding new dependencies to a project, running npm install-test ensures that the installation doesn’t break the existing functionality.
• Simplified Setup for New Developers: For developers joining a project, running npm install-test in a cloned repository ensures they have all the necessary dependencies installed and the project passes all tests with minimal setup.
• Automated Dependency Management: During automated workflows, especially in DevOps pipelines, you might want to install packages and validate their functionality in one command to minimize the risk of errors.