Running a Node.js Backend

Install the dependencies declared in package.json with npm install and distinguish warnings from installation failures.

Identify the purpose of the dev script in package.json and start it with npm run dev.

Identify the backend's successful startup message and local address, then stop and restart the development process.

Diagnose a missing package.json error caused by running npm commands from the wrong directory.

Diagnose command-not-found and missing-module errors involving Node.js, npm, or bcryptjs.

Explain what bcrypt hashing does and why a bcrypt hash cannot be decrypted to recover the password.

Confirm that bcryptjs is installed in the backend project before requiring it from Node.js.

Run a Node.js one-line script that hashes a chosen password with bcryptjs and capture the resulting hash.

Explain why hashing the same password more than once produces different valid bcrypt hashes.

Avoid exposing real passwords through copied commands, screenshots, source control, or shared terminal history.