nanofaker

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Command Line Interface ​

nanofaker includes a powerful CLI for generating fake data directly from your terminal. Perfect for quick data generation, testing, and scripting.

Installation ​

If you installed nanofaker globally, the CLI is available as nanofaker:

bash
npm install -g nanofaker

For local installations, use npx:

bash
npx nanofaker [command]

Commands ​

generate ​

Generate random data from any category and method.

bash
nanofaker generate <category> <method> [options]

Options:

  • --locale <locale> - Locale to use (af, ar, az, cs, da, de, en, eo, es, fa, fi, fr, he, hi, it, ja, ko, nl, no, pl, pt, sv, tl, tr, uk, zh)
  • --count <count> - Number of items to generate (default: 1)
  • --seed <seed> - Seed for reproducible results
  • --json - Output as JSON

Examples:

bash
# Generate a single name
nanofaker generate person fullName

# Generate 5 Spanish names
nanofaker generate person fullName --locale es --count 5

# Generate reproducible data with seed
nanofaker generate address city --seed 12345

# Output as JSON
nanofaker generate person firstName --count 3 --json

categories ​

List all available data categories.

bash
nanofaker categories

Shows all 16 categories:

  • person - Names, genders, job titles, prefixes, suffixes
  • address - Streets, cities, states, countries, postal codes
  • company - Names, industries, buzzwords, descriptors
  • internet - Email addresses, domains, URLs
  • phone - Phone numbers
  • food - Dishes, ingredients, cuisines, desserts, fruits, vegetables, meats, spices
  • animal - Dogs, cats, birds, fish, horses, rabbits, insects
  • sport - Sports names, teams, athletes
  • music - Genres, artists, songs, instruments
  • commerce - Products, adjectives, materials, departments, colors
  • book - Titles, authors, publishers, genres, series, reviews
  • vehicle - Manufacturers, models, types, fuel types, bicycles
  • word - Adjectives, adverbs, conjunctions, interjections, nouns, prepositions, verbs
  • hacker - Technical abbreviations, terms, phrases
  • system - File names, file types
  • science - Chemical elements, units, constants, scientific fields

methods ​

List all methods available for a specific category.

bash
nanofaker methods <category>

Examples:

bash
# List all person methods
nanofaker methods person

# List all food methods
nanofaker methods food

Shows each method with a live example:

Available methods in 'person':

  firstName            // "John"
  lastName             // "Doe"
  fullName             // "John Doe"
  gender               // "Male"
  jobTitle             // "Software Engineer"
  prefix               // "Mr."
  suffix               // "Jr."

locales ​

List all available locales.

bash
nanofaker locales

Shows all 26 supported locales:

  • af - Afrikaans
  • ar - Arabic
  • az - Azerbaijani
  • cs - Czech
  • da - Danish
  • de - German
  • en - English
  • eo - Esperanto
  • es - Spanish
  • fa - Persian/Farsi
  • fi - Finnish
  • fr - French
  • he - Hebrew
  • hi - Hindi
  • it - Italian
  • ja - Japanese
  • ko - Korean
  • nl - Dutch
  • no - Norwegian
  • pl - Polish
  • pt - Portuguese
  • sv - Swedish
  • tl - Filipino
  • tr - Turkish
  • uk - Ukrainian
  • zh - Chinese

batch ​

Generate multiple complete records using predefined templates.

bash
nanofaker batch <count> [options]

Options:

  • --template <template> - Template to use: user, product, address, company (default: user)
  • --locale <locale> - Locale to use
  • --seed <seed> - Seed for reproducible results

Examples:

bash
# Generate 10 users
nanofaker batch 10

# Generate 5 products in Spanish
nanofaker batch 5 --template product --locale es

# Generate reproducible data
nanofaker batch 3 --template user --seed 12345

Templates:

user ​

json
{
  "name": "John Doe",
  "email": "john.doe@example.com",
  "phone": "+1-555-123-4567",
  "city": "New York",
  "country": "United States"
}

product ​

json
{
  "name": "Ergonomic Wooden Chair",
  "description": "The beautiful range of...",
  "price": "123.45",
  "category": "Furniture",
  "sku": "ABC-12345-XYZ"
}

address ​

json
{
  "street": "Main Street",
  "city": "New York",
  "state": "California",
  "country": "United States",
  "zipCode": "90210"
}

company ​

json
{
  "name": "Tech Innovations Inc.",
  "industry": "Technology",
  "buzzword": "synergy",
  "email": "contact@techinnovations.com",
  "website": "https://techinnovations.com"
}

seed ​

Generate data with a specific seed to demonstrate reproducibility.

bash
nanofaker seed <seed> [options]

Options:

  • --category <category> - Category to use (default: person)
  • --method <method> - Method to use (default: fullName)
  • --count <count> - Number of items to generate (default: 5)

Examples:

bash
# Generate 5 names with seed
nanofaker seed 12345

# Generate 3 food dishes with seed
nanofaker seed 42 --category food --method dish --count 3

Running the same command again will produce the exact same results:

bash
$ nanofaker seed 12345

Generating with seed 12345:

1. John Doe
2. Jane Smith
3. Bob Johnson
4. Alice Williams
5. Charlie Brown

Run the same command again to get the same results!

version ​

Show the version of nanofaker.

bash
nanofaker version

Usage Examples ​

Quick Data Generation ​

bash
# Get a random name
nanofaker generate person fullName

# Get a random email
nanofaker generate internet email

# Get a random city
nanofaker generate address city

Multiple Items ​

bash
# Generate 10 names
nanofaker generate person fullName --count 10

# Generate 5 emails as JSON
nanofaker generate internet email --count 5 --json

Localization ​

bash
# Spanish name
nanofaker generate person fullName --locale es

# French address
nanofaker generate address city --locale fr

# Japanese food
nanofaker generate food dish --locale ja

Reproducible Data ​

bash
# Same seed = same results
nanofaker generate person fullName --seed 12345
nanofaker generate person fullName --seed 12345  # Same output

# Different seed = different results
nanofaker generate person fullName --seed 100
nanofaker generate person fullName --seed 200

Batch Generation ​

bash
# Generate 10 test users
nanofaker batch 10 > users.json

# Generate products for different locales
nanofaker batch 5 --template product --locale en > products-en.json
nanofaker batch 5 --template product --locale es > products-es.json
nanofaker batch 5 --template product --locale ja > products-ja.json

Scripting ​

Use the CLI in shell scripts:

bash
#!/bin/bash

# Generate test data
for i in {1..10}; do
  name=$(nanofaker generate person fullName)
  email=$(nanofaker generate internet email)
  echo "$name,$email" >> users.csv
done

Or with JSON output:

bash
# Generate 100 users and save to file
nanofaker batch 100 --template user > test-data.json

# Generate products in multiple locales
for locale in en es fr de; do
  nanofaker batch 50 --template product --locale $locale > "products-$locale.json"
done

Combining with jq ​

Use with jq for advanced JSON processing:

bash
# Generate users and extract just emails
nanofaker batch 10 | jq '.[].email'

# Generate products and filter by price
nanofaker batch 100 --template product | jq '.[] | select(.price | tonumber > 500)'

# Generate addresses and format
nanofaker batch 5 --template address | jq '.[] | "\(.city), \(.state) \(.zipCode)"'

Error Handling ​

The CLI provides helpful error messages:

bash
# Invalid category
$ nanofaker generate invalid method
Error: Category 'invalid' not found

Available categories: person, address, company, internet, phone, ...

# Invalid method
$ nanofaker generate person invalid
Error: Method 'invalid' not found in category 'person'

Available methods in person: firstName, lastName, fullName, ...

# Invalid template
$ nanofaker batch 10 --template invalid
Error: Template 'invalid' not found

Available templates: user, product, address, company

Tips ​

1. Explore Available Methods ​

Use the methods command to discover what each category offers:

bash
nanofaker methods food
nanofaker methods animal
nanofaker methods commerce

2. Use Seeds for Testing ​

Seeds ensure consistent test data:

bash
# Always get the same test user
nanofaker batch 1 --seed 42 > test-user.json

3. Pipe to Files ​

Save generated data to files:

bash
nanofaker batch 1000 --template user > users.json
nanofaker generate person fullName --count 100 > names.txt

4. Combine with Other Tools ​

bash
# Count unique first names
nanofaker generate person firstName --count 1000 | sort | uniq -c

# Generate CSV data
echo "name,email,city" > data.csv
for i in {1..100}; do
  nanofaker batch 1 | jq -r '.[] | [.name, .email, .city] | @csv' >> data.csv
done

Global Installation ​

For easier access, install nanofaker globally:

bash
npm install -g nanofaker
# or
bun add -g nanofaker

Then use it anywhere:

bash
nanofaker generate person fullName
nanofaker batch 10
nanofaker methods food

Shell Aliases ​

Create aliases for frequently used commands:

bash
# Add to ~/.bashrc or ~/.zshrc
alias fake-name='nanofaker generate person fullName'
alias fake-email='nanofaker generate internet email'
alias fake-users='nanofaker batch 10'

# Usage
fake-name
fake-email
fake-users

The nanofaker CLI is a powerful tool for quickly generating test data, seeding databases, creating mock APIs, and more!

Released under the MIT License.

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