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Weather Dashboard

Real API data with search, loading and error states.

~10 hours 6 phases
JavaScriptHTMLCSS

Overview

Build a weather dashboard that fetches real data from a public weather API, supports city search, and handles loading, error and empty states cleanly. Learn API integration, data presentation and robust async state management.

The problem

Show live weather for a searched city, handling loading, errors and empty states gracefully.

Why it matters

Every real app talks to an API; this project proves you can integrate external data and handle the real-world states that come with it.

What you'll build

  • A live weather dashboard
  • Search with debounce
  • Loading/error/empty states
  • Responsive data cards

What you'll learn

  • API integration
  • Async UI state
  • Debounced search
  • Data presentation

Business problem

Users need current, trustworthy weather with graceful handling of bad input or outages.

Technical problem

Integrate a third-party API and render its data with proper state management.

When you're done: A responsive weather dashboard that reliably queries and presents live data.

Requirements

User requirements

  • Search by city
  • See current conditions and forecast
  • Get clear feedback on errors
  • See loading state

System requirements

  • Use a public weather API
  • Graceful error and empty states

Functional requirements

  • City search
  • Current weather display
  • Forecast list
  • Loading state
  • Error and empty states

Non-functional requirements

  • Responsive
  • Clear async states
  • Debounced search

Technical requirements

  • Async fetch with error handling
  • Debounced input
  • Reusable result components

Security requirements

  • No API key committed
  • Sanitize displayed data

Operational requirements

  • Handle API rate limits and failures

Constraints

  • Frontend only
  • Free-tier public API

Success criteria

  • Search returns accurate conditions
  • Network failure shows a friendly error
  • Loading state is visible

Flows

Request Flow

  1. 1

    Browser

    User searches a city.

  2. 2

    Application

    Debounces and queries the weather API.

  3. 3

    Weather API

    Returns conditions and forecast.

  4. 4

    Application

    Renders loading, error or results.

Project Structure

Root of the client application source.

Setup

  1. 1

    Prerequisites

    You need the tools required by JavaScript, HTML, CSS installed and available on your PATH.

  2. 2

    Clone project

    Clone the repository locally.

    1. Clone the repository
    git clone <your-repo-url> <project-folder>
  3. 3

    Install dependencies

    Install the project dependencies.

    1. Initialize a Node.js project
    npm init -y

    Expected

    Creates a package.json with defaults.

    If it fails

    command not found: npm

    Fix

    Install Node.js LTS from the official site, then reopen your terminal.

  4. 4

    Configure environment

    Set the environment variables documented for this project. Never commit secrets.

    1. Create the environment file
    cp .env.example .env   # then edit values
  5. 5

    Start project

    Run the development command and confirm it starts.

    1. Start the development server
    npm run dev

    Expected

    Dev server starts; watch terminal for the local URL.

    If it fails

    Port 3000 is already in use

    Fix

    Run on another port: npm run dev -- --port 3001, or stop the conflicting process.

  6. 6

    Verify

    Open the printed local URL and confirm the primary flow works.

Build Phases

0 of 6 phases complete

  1. Objective: Establish the next milestone of the client-side interface.

    What changes: The project advances to the next coherent state, keeping the previous milestones working.

    Files touched

    Relevant source and configuration files for this milestone.

    Run

    1. Initialize a Node.js project
    npm init -y

    Expected

    Creates a package.json with defaults.

    If it fails

    command not found: npm

    Fix

    Install Node.js LTS from the official site, then reopen your terminal.

    Tasks

    • Implement the specific behaviour required for this milestone.
    • Verify the previous milestone still works.

    Validate: The milestone behaves as expected and does not break existing functionality.

    Common mistakes

    • • Skipping validation and moving on before confirming the milestone works.

  2. Objective: Establish the next milestone of the client-side interface.

    What changes: The project advances to the next coherent state, keeping the previous milestones working.

    Files touched

    Relevant source and configuration files for this milestone.

    Run

    1. Install the javascript package
    npm install javascript

    Expected

    Adds javascript to node_modules and package.json.

    If it fails

    npm ERR! network / EACCES

    Fix

    Check your network or run with sudo on Linux/macOS; on Windows run the terminal as Administrator.

    Tasks

    • Implement the specific behaviour required for this milestone.
    • Verify the previous milestone still works.

    Validate: The milestone behaves as expected and does not break existing functionality.

    Common mistakes

    • • Skipping validation and moving on before confirming the milestone works.

  3. Objective: Establish the next milestone of the client-side interface.

    What changes: The project advances to the next coherent state, keeping the previous milestones working.

    Files touched

    Relevant source and configuration files for this milestone.

    Run

    1. Start the development server
    npm run dev

    Expected

    Dev server starts; watch terminal for the local URL.

    If it fails

    Port 3000 is already in use

    Fix

    Run on another port: npm run dev -- --port 3001, or stop the conflicting process.

    Tasks

    • Implement the specific behaviour required for this milestone.
    • Verify the previous milestone still works.

    Validate: The milestone behaves as expected and does not break existing functionality.

    Common mistakes

    • • Skipping validation and moving on before confirming the milestone works.

  4. Objective: Establish the next milestone of the client-side interface.

    What changes: The project advances to the next coherent state, keeping the previous milestones working.

    Files touched

    Relevant source and configuration files for this milestone.

    Run

    1. Build the application for production
    npm run build

    Expected

    A production bundle is emitted to the output directory.

    If it fails

    Build fails with a type or syntax error

    Fix

    Read the error message, fix the referenced file, and re-run the build.

    Tasks

    • Implement the specific behaviour required for this milestone.
    • Verify the previous milestone still works.

    Validate: The milestone behaves as expected and does not break existing functionality.

    Common mistakes

    • • Skipping validation and moving on before confirming the milestone works.

  5. Objective: Establish the next milestone of the client-side interface.

    What changes: The project advances to the next coherent state, keeping the previous milestones working.

    Files touched

    Relevant source and configuration files for this milestone.

    Tasks

    • Implement the specific behaviour required for this milestone.
    • Verify the previous milestone still works.

    Validate: The milestone behaves as expected and does not break existing functionality.

    Common mistakes

    • • Skipping validation and moving on before confirming the milestone works.

  6. Objective: Establish the next milestone of the client-side interface.

    What changes: The project advances to the next coherent state, keeping the previous milestones working.

    Files touched

    Relevant source and configuration files for this milestone.

    Tasks

    • Implement the specific behaviour required for this milestone.
    • Verify the previous milestone still works.

    Validate: The milestone behaves as expected and does not break existing functionality.

    Common mistakes

    • • Skipping validation and moving on before confirming the milestone works.

Commands

1. Initialize a Node.js project
npm init -y

Expected

Creates a package.json with defaults.

If it fails

command not found: npm

Fix

Install Node.js LTS from the official site, then reopen your terminal.

2. Install the javascript package
npm install javascript

Expected

Adds javascript to node_modules and package.json.

If it fails

npm ERR! network / EACCES

Fix

Check your network or run with sudo on Linux/macOS; on Windows run the terminal as Administrator.

3. Start the development server
npm run dev

Expected

Dev server starts; watch terminal for the local URL.

If it fails

Port 3000 is already in use

Fix

Run on another port: npm run dev -- --port 3001, or stop the conflicting process.

4. Build the application for production
npm run build

Expected

A production bundle is emitted to the output directory.

If it fails

Build fails with a type or syntax error

Fix

Read the error message, fix the referenced file, and re-run the build.

Testing

Unit tests

  • Core logic and pure functions behave correctly.

    npm init -y

    Success: All unit tests pass without errors.

Integration tests

  • Components integrate correctly with data sources and services.

    npm test

    Success: Integration tests pass for the primary flows.

API tests

  • Endpoints respond to valid and invalid input correctly.

    npm test

    Success: API tests cover happy and failure paths.

End-to-end tests

  • A user can complete the primary journey end to end.

    npm run test:e2e

    Success: The main user journey completes successfully.

Security tests

  • No obvious security regressions are introduced.

    npm audit

    Success: No high or critical vulnerabilities.

Debugging & Troubleshooting

Port already in use at startup

Why: Another process is binding the same port your app wants.

Check: List what is using the port.

lsof -i :3000   # Linux/macOS  |  netstat -ano | findstr :3000   # Windows

Fix: Free the port or start your app on a different port.

Prevent: Choose uncommon ports and document them in the README.

Environment variable missing or undefined

Why: A required value was not loaded into the runtime.

Check: Print the variable or inspect the config loader.

echo $MY_VAR   # Linux/macOS  |  echo %MY_VAR%   # Windows

Fix: Add the variable to your .env file and restart the process.

Prevent: Fail fast at startup when required env vars are absent.

API request times out

Why: An upstream call is slow or the network is blocked.

Check: Time a direct request against the upstream.

curl -w 'time_total: %{time_total}\n' http://upstream/health

Fix: Add timeouts and retries to the client; verify the upstream is up.

Prevent: Set explicit timeouts and circuit breakers on outbound calls.

Dependency fails to install or run

Why: Version conflicts or an incompatible runtime.

Check: Inspect the error and the installed versions.

npm ls <pkg>

Fix: Align versions or clear the lockfile and reinstall.

Prevent: Commit a lockfile and use the same Node version everywhere.

Security

Security is treated as a core requirement: input is validated, secrets are protected, and dependencies are kept up to date.

  • Input validation

    Validate and sanitize all user input before use.

  • Secrets management

    Store secrets in environment variables, never in source.

  • Dependency hygiene

    Regularly audit dependencies for known vulnerabilities.

Observability

Logs

  • Structured request logs with correlation IDs
  • Application-level error logs

Metrics

  • Request latency
  • Error rate
  • Throughput

Traces

  • Request tracing across the API and data layer

Health checks

  • A /health endpoint reporting readiness

Alerts

  • High error rate alert
  • Latency threshold alert

Dashboards

  • A dashboard showing requests, latency and errors

SLIs

  • Availability — Fraction of successful requests over the window
  • Latency — P95 response time

SLOs

  • Availability — 99.9% over 30 days
  • Latency — P95 under 500ms

Deployment

  1. 1

    Prepare for deployment

    Build the production artifact.

    1. Build for production
    npm run build
  2. 2

    Deploy

    Deploy to the project target platform following its documented steps.

    1. Deploy
    npm run deploy   # or the platform-specific command
  3. 3

    Verify

    Confirm the deployed application responds and its health check passes.

    1. Check health
    curl -I https://<your-deployed-url>

Documentation

Project Overview

Build a weather dashboard that fetches real data from a public weather API, supports city search, and handles loading, error and empty states cleanly. Learn API integration, data presentation and robust async state management. This is a intermediate ui project in the client-side interface space, built to demonstrate real engineering, not just copied code.

What You Will Build

- A live weather dashboard - Search with debounce - Loading/error/empty states - Responsive data cards

Problem Statement

Users need current, trustworthy weather with graceful handling of bad input or outages. Integrate a third-party API and render its data with proper state management.

Technology Stack

JavaScript, HTML, CSS

Installation

Clone the repository and install dependencies with the documented commands.

Local Development

Run the development command and open the printed local URL.

Testing

Run the test commands documented in the Testing section and confirm they pass.

Deployment

Follow the documented deployment steps for this project's target platform.

Interview Explanation

Use the Interview section to explain the architecture, technology choices and trade-offs.

Build Process

Phases guide the build in 6 checkpoints. Complete each and validate before moving on.

Interview Prep

30-second pitch

I built Weather Dashboard — show live weather for a searched city, handling loading, errors and empty states gracefully. It uses JavaScript, HTML, CSS and solves users need current, trustworthy weather with graceful handling of bad input or outages.

2-minute walkthrough

Build a weather dashboard that fetches real data from a public weather API, supports city search, and handles loading, error and empty states cleanly. Learn API integration, data presentation and robust async state management. The core requirements were City search, Current weather display, Forecast list. I structured the work around Fetch and process external data, Manage async UI states, Implement search with debounce and validated the result with the documented tests.

Architecture

Because this is a frontend project, the architecture is concentrated in client-side interface rather than a distributed system.

Why these technologies

I chose JavaScript, HTML, CSS because they are the pragmatic, well-supported tools best suited to building a ui of this kind.

Why this architecture

The structure exists to keep concerns separated, make each piece testable, and scale the project cleanly as requirements grow.

At scale

At scale I would introduce caching, move to a service boundary structure, add proper observability, and enforce stricter contracts between components.

What can fail

The data source becomes unavailable, A dependency introduces a breaking change, Performance degrades under load, Configuration drift between environments

Monitoring

Monitoring is covered in the Observability section, focusing on requests, latency, errors and health checks.

Security

Security was handled by validating input, protecting secrets, and following the practices listed in the Security section.

Deployment strategy

Deployment follows the steps in the Deployment section for the target platform, with a health check to confirm success.

What I'd do differently

With more time I would add deeper test coverage, stronger observability, and automated deployment.

Practice Q&A

Why did you build Weather Dashboard?

To demonstrate Fetch and process external data and Manage async UI states on a real, portfolio-worthy project.

What was the hardest part?

Coordinating the pieces so each stays correct as the project grows, and validating end to end.

How do you handle failure and scale?

By designing for correctness first and adding resilience once the core works.

Extensions

  • Add deeper test coverage
  • Add observability and alerting
  • Harden security
  • Automate deployment

Completion Checklist

Prerequisite Projects

Next Steps

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