JavaScript Node.js Basics 5

Question 1

What is the purpose of the `package-lock.json` file in a Node.js project?

Accepted Answer

It locks the exact versions of all installed dependencies for reproducible installs

Answer

`package-lock.json` records the exact resolved versions and integrity hashes of every package in the dependency tree, ensuring identical installs across environments.

Question 2

What does `npm install --save-dev` do differently from `npm install`?

Accepted Answer

It installs packages and records them under `devDependencies` in package.json

Answer

`--save-dev` (or `-D`) adds the package to `devDependencies`, signaling it is only needed during development and testing, not in production.

Question 3

Which file do you create to prevent npm from publishing specific files or folders in your package?

Accepted Answer

.npmignore

Answer

`.npmignore` works like `.gitignore` but specifically controls which files are excluded from the tarball when you run `npm publish`.

Question 4

What does the `exports` field in `package.json` allow you to define?

Accepted Answer

Conditional and subpath exports that control which files external consumers can import

Answer

The `exports` field lets package authors map subpaths and conditions (e.g., `import`, `require`, `browser`) to specific file paths, enabling encapsulation of internal modules.

Question 5

What does Node.js's `util.promisify()` do?

Accepted Answer

It wraps a Node.js-style callback function so it returns a Promise instead

Answer

`util.promisify()` takes a function that follows the Node.js error-first callback convention and returns a version that returns a Promise.

JavaScript Practice Test

JavaScript Practice Test

JavaScript Node.js Basics 5