About Chance
Overview Chance is a minimalist library for generating random strings, numbers, names, addresses, and other data types. It was created to reduce the monotony of writing automated tests and building prototypes that need random placeholder data. The library runs in Node.js, the browser (via script tag, RequireJS, or Bower), and the command line. It is open source under the MIT license and depends on a Mersenne Twister pseudo-random number generator. Key Benefits Generates over 40 types of random data including names, addresses, text, and finance values. Works across Node, browser, and CLI environments with zero external dependencies. Production build is 17 KB gzipped (55 KB minified, 95 KB development). Provides seeded random generation for reproducible test data. Released under the business-friendly MIT open source license. Includes helpers such as pick, pickone, pickset, set, shuffle, and mixin. How It Works You install the package via npm, Bower, or drop a script tag into your HTML page. Once loaded, you call chainable methods from the Chance instance — for example, new Chance().name() returns a random full name, new Chance().sentence() returns a random sentence, and new Chance().ssn() returns a random social security number. Each generator method accepts optional parameters to constrain the output, and you can pass a seed to the constructor for reproducible sequences. Use Cases Software engineers writing automated tests that need realistic but fake names, addresses, or phone numbers. Front-end developers building UI prototypes or design mockups that require placeholder content. Data engineers seeding databases or generating sample datasets for performance benchmarks. Educators and students learning JavaScript who need a simple, predictable source of random data. API developers stress-testing endpoints with varied random payloads. Why Choose This Product Chance is best suited for developers who need deterministic random data (via seeding) in JavaScript environments. It explicitly warns against use in cryptographic applications because it relies on a Mersenne Twister algorithm — not truly random entropy sources.
Chance Pros & Cons
- Works in Node, browser, and CLI
- Seeded generation for reproducible tests
- 40+ data type generators
- 17 KB gzipped production build
- MIT license — free for commercial use
Key Features
Random primitives
Returns random boolean, character, floating-point number, integer, letter, natural number, prime, or string values.
Person data
Generates random person data including age, birthday, first name, last name, gender, prefix, suffix, SSN, and full name.
Animal names
Produces random animal names and types from a built-in dictionary.
Mobile identifiers
Generates mobile device identifiers such as Android ID, Apple push notification token, BlackBerry PIN, and Windows Phone ANID/ANID2.
Web data
Returns random web-related strings like avatar URL, color, company name, domain, email, Facebook ID, Google Analytics ID, hashtag, IP, IPv6, Klout score, profession, top-level domain, Twitter handle, and URL.
Location data
Generates random address components including altitude, area code, city, coordinates, country, depth, geohash, latitude, locale, longitude, phone, postal code, province, state, street, and ZIP code.
Time data
Returns random time-related values including AM/PM, date, hour, millisecond, minute, month, second, timestamp, timezone, weekday, and year.
Finance data
Generates random finance values like credit card number, credit card type, currency pair, dollar amount, euro amount, expiration month, and expiration year.
Helper utilities
Provides utility helpers for capitalizing strings, mixing in custom methods, padding numbers, picking one or multiple items from arrays, shuffling, and setting custom generation rules.
Miscellaneous generators
Generates special-purpose random values including coin flips, dice rolls, GUIDs, hashes, hidden fields, radio button selections, RPG-style dice, TV identifiers, unique values, and weighted selections.