referral-codes

Referral Code Generator

This package is now using ESM. Please use v2 is you still need commonjs. Requires Node v18+

Generate unique, random, and hard to guess coupon / voucher codes. Use cases: promo codes, loyalty coupons, gift vouchers, in-app purchases, referral links

This library originates from voucher-code-generator.

I re-wrote this library using the same API, but with more modern syntax and more performant constructs.

Installation

Install with yarn:

$ yarn add referral-codes

Install with npm:

$ npm install -save referral-codes

Usage

Generate 5 codes, each 8 characters long:

referralCodes.generate({
  length: 8,
  count: 5,
});

Sample result: ["FR6bwx1q", "ByamOdWV", "7roFwfQs", "rmWlwvll", "pgih5eAB"]

Charset

Default charset is alphanumeric (numbers and letters). However, you can specify your own charset:

referralCodes.generate({
  length: 6,
  count: 3,
  charset: '0123456789',
});

Sample result: ["386525", "676442", "019075"]

You can also use one of the predefined charsets by calling referralCodes.charset(name).

name	charset
"numbers"	"0123456789"
"alphabetic"	"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
"alphanumeric"	"0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"

Constants for these defaults can also be used to avoid issues with misspellings and help with intellisense

For example:

referralCodes.generate({
  length: 5,
  count: 4,
  charset: referralCodes.charset('alphabetic'),
});

or

referralCodes.generate({
  length: 5,
  count: 4,
  charset: referralCodes.charset(referralCodes.Charset.ALPHABETIC),
});

Result: ["odghy", "kZEYc", "eOTCl", "wVCzD"]

Prefix and Postfix

You can optionally surround each generated code with a prefix and/or postfix.

For instance:

referralCodes.generate({
  prefix: 'promo-',
  postfix: '-2015',
});

Result: ["promo-WZ4x1t3U-2015"]

Pattern

Codes may follow a specified pattern. Use hash (#) as a placeholder for random characters. Note that if pattern is specified then length is ignored.

Example:

referralCodes.generate({
  pattern: '##-###-##',
});

Result: ["P7-ofW-Ka"]

Infeasible configs

There exist some configs that are not feasible. For example it's not possible to generate 1500 codes if you want your codes to be 2 characters long and consisting only of numbers. Referral code generator detects such cases and throws an error "Not possible to generate requested number of codes.".

try {
  referralCodes.generate({
    count: 1500,
    length: 2,
    charset: '0123456789',
  });
} catch (e) {
  console.log('Sorry, not possible.');
}

Config reference

attribute	default value	description
length	8	Number of characters in a generated code (excluding prefix and postfix)
count	1	Number of codes generated.
charset	alphanumeric	Characters that can appear in the code.
prefix	""	A text appended before the code.
postfix	""	A text appended after the code.
pattern	"########"	A pattern for codes where hashes (#) will be replaced with random characters.

Testing

Install dependencies:

$ yarn

Run tests:

$ yarn test

Benchmarks

Benchmarks were run using the benchmark library on a 2019 Macbook Pro 2.6Ghz 6-Core Intel i7 with 32GB 2667MHz RAM

with 10 codes x 212,877 ops/sec ±1.81% (84 runs sampled)
with 100 codes x 24,421 ops/sec ±1.50% (86 runs sampled)
with 1000 codes x 2,278 ops/sec ±1.50% (84 runs sampled)

Run benchmarks:

$ yarn benchmark

License

Code released under the MIT license.