Running Locally

Move from the page to ordinary files

Download the reading-queue project. It contains the actual model, controller, service, UI, HTML, and automated tests. The in-page preview requires no installation; these steps are for learning how the same project runs outside the course.

1. Install a current Node.js LTS release from the official Node site. Node executes JavaScript outside the browser. Its npm tool can run project commands.
2. Extract the ZIP. Open a terminal in the extracted folder containing package.json. A terminal runs typed commands in its current folder; it is separate from a JavaScript console editor.
3. Run node --version to verify installation. Run npm test to execute the included tests. No npm install is needed: the project uses only Node built-ins.
4. Run npm start, leave that terminal open, and visit http://127.0.0.1:8080. Stop the local server with Ctrl+C. If the port is occupied, the included README explains changing it.

package.json declares type=module so Node interprets .js files as ES modules. Its scripts map npm test to Node’s test runner and npm start to the included server. In "type": "module", type is a package.json configuration field, not an HTML attribute. Each command runs in the folder containing that file. The browser loads app.js as a module from index.html. The server serves only the listed local assets and is not a production hosting setup.

Do not paste terminal commands into a JavaScript editor or double-click the modular index.html. Relative browser modules need the HTTP-served origin. If a module fails, inspect its exact path and export name before changing its logic. Browser developer tools show Console errors and Network requests: open your browser’s Developer Tools menu, select Console or Network, then reload. Paths in Network should refer to the local project.

The tests use node:test to define cases and node:assert/strict for assertions. Inspect one test and its inputs before running it. The runtime is a tool; understanding why a case protects a contract matters more than memorizing a command.

Predict and trace

Write the output before running. Follow the values through each call; if your prediction differs, identify the first step that surprised you.

const scripts = {
  test: "node --test project.test.js",
  start: "node server.mjs"
};

console.log(scripts.test);
console.log(scripts.start);

node --test project.test.js
node server.mjs

Build it yourself

const files = ["index.html", "model.js", "app.js", "README.md"];

function projectSummary(files) {
  return files.filter(name => name.endsWith(".js")).join(", ");
}

console.log(projectSummary(["index.html", "model.js", "app.js", "README.md"]));

model.js, app.js

Test a changed requirement

Run npm test locally, deliberately break one guarded rule in model.js, and confirm a test fails. Restore the change and rerun. If you stay in the browser, perform the same experiment on a console assertion.

Explain before moving on

Which environment runs the UI and which runs the tests? What does package.json configure?

Going further

The last project test checks page-lifecycle wiring with a small DOM double. It uses Node’s vm module to run app.js with controlled browser-like objects. That instrumentation is optional reading; you can understand the model and controller tests without learning vm. Browser keyboard and history-navigation checks are still needed for the real UI.

Read Node’s built-in test runner documentation after working through the examples. Use it as a reference when you meet an unfamiliar option; finishing every reference section is not required for this course.