Install packages from package.json using only the lockfile
📦 Node.js-> Command Line
✨ The Prompt Phrase
npm ci
💻 Code Preview
📦 All-in-One Code
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<title>Install packages from package.json using only the lockfile - Interactive Tutorial</title>
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<style>
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--bg-secondary: #151932;
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position: fixed;
width: 10px;
height: 10px;
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animation: confetti-fall 3s linear forwards;
z-index: 9999;
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to {
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.command-display { font-size: 1rem; padding: 15px 20px; }
.section-title { font-size: 1.8rem; }
.card { padding: 25px; }
.step { padding-left: 80px; }
.step::before { width: 50px; height: 50px; font-size: 1.5rem; }
.comparison-grid { grid-template-columns: 1fr; }
}
</style>
</head>
<body>
<div class="progress-container">
<div class="progress-bar" id="progressBar"></div>
</div>
<div class="hero">
<div class="hero-content">
<div class="npm-icon">📦</div>
<h1>Master npm ci!</h1>
<div class="command-display">npm ci</div>
<p>Clean, fast, reproducible installs! 🚀</p>
</div>
</div>
<div class="container">
<!-- What Is It -->
<section class="section">
<h2 class="section-title">🤔 What Is npm ci?</h2>
<div class="card">
<p style="font-size: 1.2rem; margin-bottom: 20px;">
<code>npm ci</code> stands for <span class="highlight">"Clean Install"</span> - it's a faster, more reliable way to install packages that's designed for <strong>automated environments</strong> like CI/CD pipelines! 📦
</p>
<p style="margin-bottom: 20px;">
Think of it like building IKEA furniture! 🛋️ <code>npm install</code> is like freestyle building - you can modify the instructions, swap parts, and the final result might vary. <code>npm ci</code> is like following the exact instructions with the exact parts - you get the SAME result every single time, guaranteed!
</p>
<div class="info">
<strong>Breaking It Down:</strong>
<ul style="margin-left: 30px; margin-top: 10px; line-height: 2;">
<li><code class="code-npm">npm</code> - Node Package Manager</li>
<li><code class="code-ci">ci</code> - Clean Install (Continuous Integration)</li>
<li>Installs from <code>package-lock.json</code> ONLY</li>
<li>Deletes <code>node_modules</code> first</li>
<li>Faster and more reliable than <code>npm install</code></li>
</ul>
</div>
<div style="margin-top: 30px;">
<h3 style="color: var(--accent-pink); margin-bottom: 15px;">Why "ci"? 🔍</h3>
<p>CI stands for "Continuous Integration" - the practice of automatically testing code. <code>npm ci</code> was designed for these automated environments where you need <strong>exact, reproducible builds</strong> every time!</p>
</div>
</div>
</section>
<!-- Comparison -->
<section class="section">
<h2 class="section-title">📊 npm install vs npm ci</h2>
<div class="card">
<h3 style="margin-bottom: 20px; text-align: center;">See The Difference! 🎯</h3>
<div class="comparison-grid">
<div class="comparison-item install">
<h4 style="color: var(--accent-red); margin-bottom: 15px;">🔴 npm install</h4>
<ul style="margin-left: 20px; line-height: 2;">
<li>Updates package-lock.json</li>
<li>Can install different versions</li>
<li>Keeps existing node_modules</li>
<li>Slower (checks compatibility)</li>
<li>Good for development</li>
</ul>
<p style="margin-top: 15px; font-size: 0.9rem; color: var(--text-secondary);">😐 Flexible but less predictable</p>
</div>
<div class="comparison-item ci">
<h4 style="color: var(--accent-green); margin-bottom: 15px;">✅ npm ci</h4>
<ul style="margin-left: 20px; line-height: 2;">
<li>Never modifies package-lock.json</li>
<li>Installs exact versions</li>
<li>Deletes node_modules first</li>
<li>Faster (no compatibility checks)</li>
<li>Perfect for CI/CD</li>
</ul>
<p style="margin-top: 15px; font-size: 0.9rem; color: var(--text-secondary);">🚀 Fast, reliable, reproducible!</p>
</div>
</div>
</div>
</section>
<!-- Why Use It -->
<section class="section">
<h2 class="section-title">✨ Why Use npm ci?</h2>
<div class="card">
<div class="feature-grid">
<div class="feature-card">
<div class="feature-icon">⚡</div>
<div class="feature-title">Faster</div>
<p style="color: var(--text-secondary);">2-10x faster installs!</p>
</div>
<div class="feature-card">
<div class="feature-icon">🔒</div>
<div class="feature-title">Reproducible</div>
<p style="color: var(--text-secondary);">Same result every time!</p>
</div>
<div class="feature-card">
<div class="feature-icon">🧹</div>
<div class="feature-title">Clean</div>
<p style="color: var(--text-secondary);">Fresh node_modules!</p>
</div>
<div class="feature-card">
<div class="feature-icon">🎯</div>
<div class="feature-title">Exact Versions</div>
<p style="color: var(--text-secondary);">No surprises!</p>
</div>
<div class="feature-card">
<div class="feature-icon">🤖</div>
<div class="feature-title">CI/CD Ready</div>
<p style="color: var(--text-secondary);">Built for automation!</p>
</div>
<div class="feature-card">
<div class="feature-icon">🛡️</div>
<div class="feature-title">Safer</div>
<p style="color: var(--text-secondary);">No accidental updates!</p>
</div>
</div>
</div>
</section>
<!-- How It Works -->
<section class="section">
<h2 class="section-title">⚙️ How Does It Work?</h2>
<div class="card">
<div class="steps">
<div class="step">
<h3>Step 1: Check for package-lock.json</h3>
<p>npm ci requires package-lock.json to exist. If missing, it fails!</p>
</div>
<div class="step">
<h3>Step 2: Delete node_modules</h3>
<p>Completely removes existing node_modules folder.</p>
</div>
<div class="step">
<h3>Step 3: Read Lockfile</h3>
<p>Reads exact versions from package-lock.json.</p>
</div>
<div class="step">
<h3>Step 4: Install Packages</h3>
<p>Downloads and installs exact versions specified.</p>
</div>
<div class="step">
<h3>Step 5: Verify Integrity</h3>
<p>Checks package integrity using checksums.</p>
</div>
<div class="step">
<h3>Step 6: Done!</h3>
<p>Fresh, clean, reproducible node_modules! 🎉</p>
</div>
</div>
</div>
</section>
<!-- Live Demo -->
<section class="section">
<h2 class="section-title">🎮 Interactive Demo</h2>
<div class="demo-container">
<div style="margin-bottom: 30px; text-align: center;">
<h4 style="margin-bottom: 15px;">See npm ci in Action! 📦</h4>
<button class="demo-button" onclick="simulateInstall()">
<span>🔴</span>
<span>npm install</span>
</button>
<button class="demo-button" onclick="simulateCi()">
<span>✅</span>
<span>npm ci</span>
</button>
<button class="demo-button" onclick="simulateComparison()">
<span>⚖️</span>
<span>Speed Comparison</span>
</button>
</div>
<div class="terminal" id="terminal">
<div class="terminal-line">
<span class="terminal-prompt">$</span>
<span style="color: var(--text-secondary);"> Ready to install packages...</span>
</div>
</div>
</div>
</section>
<!-- Code Breakdown -->
<section class="section">
<h2 class="section-title">💻 Usage Examples</h2>
<div class="card">
<div class="tabs">
<button class="tab active" onclick="switchTab('basic')">Basic Usage</button>
<button class="tab" onclick="switchTab('cicd')">CI/CD Setup</button>
<button class="tab" onclick="switchTab('docker')">Docker</button>
<button class="tab" onclick="switchTab('tips')">Pro Tips</button>
</div>
<div id="basic" class="tab-content active">
<h3 style="color: var(--accent-pink); margin-bottom: 15px;">Basic Usage</h3>
<div class="code-block">
<div class="code-header">
<div class="terminal-dots">
<div class="terminal-dot dot-red"></div>
<div class="terminal-dot dot-yellow"></div>
<div class="terminal-dot dot-green"></div>
</div>
<button class="copy-btn" onclick="copyCode('basic-code')">📋 Copy</button>
</div>
<pre><code id="basic-code"><span class="code-comment"># Clean install from lockfile</span>
npm ci
<span class="code-comment"># What it does:</span>
<span class="code-comment"># 1. Requires package-lock.json to exist</span>
<span class="code-comment"># 2. Deletes node_modules/</span>
<span class="code-comment"># 3. Installs exact versions from lockfile</span>
<span class="code-comment"># 4. Never modifies package-lock.json</span>
<span class="code-comment"># When to use npm ci:</span>
<span class="code-comment"># ✅ CI/CD pipelines</span>
<span class="code-comment"># ✅ Production deployments</span>
<span class="code-comment"># ✅ Fresh project setup</span>
<span class="code-comment"># ✅ After pulling changes</span></code></pre>
</div>
<div class="success" style="margin-top: 15px;">
<strong>Result:</strong> Fast, reproducible installation!
</div>
</div>
<div id="cicd" class="tab-content">
<h3 style="color: var(--accent-pink); margin-bottom: 15px;">CI/CD Pipeline Setup</h3>
<div class="code-block">
<div class="code-header">
<div class="terminal-dots">
<div class="terminal-dot dot-red"></div>
<div class="terminal-dot dot-yellow"></div>
<div class="terminal-dot dot-green"></div>
</div>
<button class="copy-btn" onclick="copyCode('cicd-code')">📋 Copy</button>
</div>
<pre><code id="cicd-code"><span class="code-comment"># GitHub Actions</span>
name: CI
on: [push]
jobs:
build:
runs-on: ubuntu-latest
steps:
- uses: actions/checkout@v3
- uses: actions/setup-node@v3
- run: npm ci <span class="code-comment"># Use ci, not install!</span>
- run: npm test
<span class="code-comment"># GitLab CI</span>
test:
script:
- npm ci
- npm test
<span class="code-comment"># Jenkins</span>
sh <span class="code-string">'npm ci'</span>
sh <span class="code-string">'npm test'</span>
<span class="code-comment"># package.json scripts</span>
{
<span class="code-string">"scripts"</span>: {
<span class="code-string">"ci"</span>: <span class="code-string">"npm ci && npm test"</span>
}
}</code></pre>
</div>
<div class="tip" style="margin-top: 15px;">
<strong>Pro Tip:</strong> Always use npm ci in CI/CD for consistent builds!
</div>
</div>
<div id="docker" class="tab-content">
<h3 style="color: var(--accent-pink); margin-bottom: 15px;">Docker Optimization</h3>
<div class="code-block">
<div class="code-header">
<div class="terminal-dots">
<div class="terminal-dot dot-red"></div>
<div class="terminal-dot dot-yellow"></div>
<div class="terminal-dot dot-green"></div>
</div>
<button class="copy-btn" onclick="copyCode('docker-code')">📋 Copy</button>
</div>
<pre><code id="docker-code"><span class="code-comment"># Dockerfile - Optimized with npm ci</span>
FROM node:18-alpine
WORKDIR /app
<span class="code-comment"># Copy package files first (for layer caching)</span>
COPY package*.json ./
<span class="code-comment"># Use npm ci for production builds</span>
RUN npm ci --only=production
<span class="code-comment"># Copy rest of application</span>
COPY . .
CMD [<span class="code-string">"node"</span>, <span class="code-string">"app.js"</span>]
<span class="code-comment"># Why npm ci in Docker?</span>
<span class="code-comment"># ✅ Faster builds</span>
<span class="code-comment"># ✅ Reproducible images</span>
<span class="code-comment"># ✅ Better layer caching</span>
<span class="code-comment"># ✅ Smaller image size</span></code></pre>
</div>
</div>
<div id="tips" class="tab-content">
<h3 style="color: var(--accent-pink); margin-bottom: 15px;">Pro Tips & Tricks</h3>
<div class="code-block">
<div class="code-header">
<div class="terminal-dots">
<div class="terminal-dot dot-red"></div>
<div class="terminal-dot dot-yellow"></div>
<div class="terminal-dot dot-green"></div>
</div>
<button class="copy-btn" onclick="copyCode('tips-code')">📋 Copy</button>
</div>
<pre><code id="tips-code"><span class="code-comment"># Install only production dependencies</span>
npm ci --only=production
<span class="code-comment"># or</span>
npm ci --omit=dev
<span class="code-comment"># Ignore scripts (security)</span>
npm ci --ignore-scripts
<span class="code-comment"># When npm ci fails:</span>
<span class="code-comment"># 1. Make sure package-lock.json exists</span>
<span class="code-comment"># 2. Ensure it's in sync with package.json</span>
<span class="code-comment"># 3. Regenerate if needed:</span>
npm install <span class="code-comment"># Updates lockfile</span>
git add package-lock.json
git commit -m <span class="code-string">"Update lockfile"</span>
<span class="code-comment"># Speed comparison:</span>
time npm install <span class="code-comment"># ~45 seconds</span>
time npm ci <span class="code-comment"># ~15 seconds (3x faster!)</span>
<span class="code-comment"># Use in package.json scripts:</span>
{
<span class="code-string">"scripts"</span>: {
<span class="code-string">"setup"</span>: <span class="code-string">"npm ci"</span>,
<span class="code-string">"fresh"</span>: <span class="code-string">"rm -rf node_modules && npm ci"</span>
}
}</code></pre>
</div>
</div>
</div>
</section>
<!-- Common Mistakes -->
<section class="section">
<h2 class="section-title">❌ Common Mistakes</h2>
<div class="card">
<div class="accordion">
<div class="accordion-item">
<div class="accordion-header" onclick="toggleAccordion(this)">
<span><strong>1. Using npm ci in Development</strong></span>
<span class="accordion-icon">▼</span>
</div>
<div class="accordion-content">
<div class="accordion-body">
<div class="warning">
<strong>Problem:</strong> npm ci deletes node_modules every time - slow for dev!
</div>
<div class="success" style="margin-top: 15px;">
<strong>Solution:</strong> Use <code>npm install</code> for development, <code>npm ci</code> for CI/CD!
</div>
</div>
</div>
</div>
<div class="accordion-item">
<div class="accordion-header" onclick="toggleAccordion(this)">
<span><strong>2. Missing package-lock.json</strong></span>
<span class="accordion-icon">▼</span>
</div>
<div class="accordion-content">
<div class="accordion-body">
<div class="warning">
<strong>Problem:</strong> npm ci fails if package-lock.json doesn't exist
</div>
<div class="success" style="margin-top: 15px;">
<strong>Solution:</strong> Run <code>npm install</code> first to generate it, then commit!
</div>
</div>
</div>
</div>
<div class="accordion-item">
<div class="accordion-header" onclick="toggleAccordion(this)">
<span><strong>3. Out of Sync Lockfile</strong></span>
<span class="accordion-icon">▼</span>
</div>
<div class="accordion-content">
<div class="accordion-body">
<div class="warning">
<strong>Problem:</strong> package.json and package-lock.json don't match
</div>
<div class="success" style="margin-top: 15px;">
<strong>Solution:</strong> Run <code>npm install</code> to sync, then commit the updated lockfile!
</div>
</div>
</div>
</div>
<div class="accordion-item">
<div class="accordion-header" onclick="toggleAccordion(this)">
<span><strong>4. Not Committing Lockfile</strong></span>
<span class="accordion-icon">▼</span>
</div>
<div class="accordion-content">
<div class="accordion-body">
<div class="warning">
<strong>Problem:</strong> .gitignore excludes package-lock.json
</div>
<div class="success" style="margin-top: 15px;">
<strong>Solution:</strong> ALWAYS commit package-lock.json! It's essential for npm ci!
</div>
</div>
</div>
</div>
</div>
</div>
</section>
<!-- Pro Tips -->
<section class="section">
<h2 class="section-title">🚀 Pro Tips</h2>
<div class="card">
<div class="tip">
<strong>CI/CD always</strong> - Use npm ci in ALL automated environments!
</div>
<div class="tip">
<strong>Commit lockfile</strong> - Always commit package-lock.json to version control!
</div>
<div class="tip">
<strong>Docker optimization</strong> - Copy package*.json first for better caching!
</div>
<div class="tip">
<strong>Production flag</strong> - Use <code>--only=production</code> for smaller deployments!
</div>
<div class="tip">
<strong>Speed matters</strong> - npm ci is 2-10x faster than npm install!
</div>
<div class="tip">
<strong>Reproducible builds</strong> - npm ci guarantees same result every time!
</div>
<div class="tip">
<strong>Fresh installs</strong> - Use npm ci when setting up new environments!
</div>
</div>
</section>
<!-- Quiz -->
<section class="section">
<h2 class="section-title">🎯 Knowledge Check Quiz</h2>
<div class="quiz-container">
<p style="margin-bottom: 30px; font-size: 1.1rem;">Test your understanding! 🧠</p>
<div class="quiz-question">
<h3>Question 1: What does "ci" stand for?</h3>
<div class="quiz-options">
<div class="quiz-option" onclick="checkAnswer(this, false, 1)">A) Code Install</div>
<div class="quiz-option" onclick="checkAnswer(this, true, 1)">B) Clean Install (Continuous Integration)</div>
<div class="quiz-option" onclick="checkAnswer(this, false, 1)">C) Complete Install</div>
</div>
<div class="quiz-feedback" id="feedback1"></div>
</div>
<div class="quiz-question">
<h3>Question 2: What does npm ci do first?</h3>
<div class="quiz-options">
<div class="quiz-option" onclick="checkAnswer(this, false, 2)">A) Updates package.json</div>
<div class="quiz-option" onclick="checkAnswer(this, true, 2)">B) Deletes node_modules folder</div>
<div class="quiz-option" onclick="checkAnswer(this, false, 2)">C) Creates a backup</div>
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<h3>Question 3: When should you use npm ci?</h3>
<div class="quiz-options">
<div class="quiz-option" onclick="checkAnswer(this, false, 3)">A) Only during development</div>
<div class="quiz-option" onclick="checkAnswer(this, true, 3)">B) In CI/CD pipelines and production</div>
<div class="quiz-option" onclick="checkAnswer(this, false, 3)">C) Never - it's deprecated</div>
</div>
<div class="quiz-feedback" id="feedback3"></div>
</div>
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<h3 style="color: var(--accent-green); font-size: 1.5rem;">🎉 Quiz Complete!</h3>
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</div>
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</section>
<!-- Summary Card -->
<section class="section">
<h2 class="section-title">📚 Quick Reference</h2>
<div class="cheat-sheet">
<h3 style="margin-bottom: 20px; font-size: 2rem;">npm ci Cheat Sheet! 🔖</h3>
<div class="cheat-grid">
<div class="cheat-item">
<h4>📦 Command</h4>
<p><code>npm ci</code></p>
<p style="font-size: 0.85rem; margin-top: 5px;">Clean install</p>
</div>
<div class="cheat-item">
<h4>🎯 Purpose</h4>
<p>Reproducible installs</p>
<p style="font-size: 0.85rem; margin-top: 5px;">From lockfile only</p>
</div>
<div class="cheat-item">
<h4>⚡ Speed</h4>
<p>2-10x faster</p>
<p style="font-size: 0.85rem; margin-top: 5px;">Than npm install</p>
</div>
<div class="cheat-item">
<h4>🧹 Behavior</h4>
<p>Deletes node_modules</p>
<p style="font-size: 0.85rem; margin-top: 5px;">Fresh install</p>
</div>
<div class="cheat-item">
<h4>🔒 Lockfile</h4>
<p>Never modifies</p>
<p style="font-size: 0.85rem; margin-top: 5px;">Read-only</p>
</div>
<div class="cheat-item">
<h4>🏭 Production</h4>
<p><code>npm ci --only=production</code></p>
<p style="font-size: 0.85rem; margin-top: 5px;">No dev deps</p>
</div>
<div class="cheat-item">
<h4>✅ Use For</h4>
<p>CI/CD, Docker, Production</p>
<p style="font-size: 0.85rem; margin-top: 5px;">Automated builds</p>
</div>
<div class="cheat-item">
<h4>❌ Don't Use</h4>
<p>Daily development</p>
<p style="font-size: 0.85rem; margin-top: 5px;">Use npm install</p>
</div>
</div>
</div>
</section>
<!-- Footer -->
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<h2 style="font-size: 2rem; margin-bottom: 20px; color: var(--accent-pink);">🎉 Congratulations!</h2>
<p style="font-size: 1.2rem; margin-bottom: 20px;">You now understand <strong>npm ci</strong>! 🚀</p>
<div style="margin: 30px 0;">
<span class="badge">📦 Package Pro</span>
<span class="badge">🚀 CI/CD Expert</span>
<span class="badge">⚡ Speed Master</span>
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