Referentially tranparent random generation functions
something(rand)boolean(rand)char(rand)date(rand)digit(rand)falsy(rand)futureDate(rand)hexadecimalDigit(rand)hexColor(rand)integer(rand)letter(rand)letters(rand, length = () => 20)negativeInteger(rand)negativeNumber(rand)number(rand)pastDate(rand)pick(rand, items = [])positiveInteger(rand)positiveNumber(rand)rangedDate(rand, range = [new Date(-1), new Date(1)])rangedInteger(rand, range)rangedNumber(rand, range = [-1, 1])sometimes(rand, doFn = v => v, value, ratio = 0.5)Referential transparency is nice. What I was missing was a simple random generation library that works predictably.
This is achieved by passing the random function as an argument. It leaves it up to you to use Math.random or your favorite pseudo random function instead.
All random generation functions take a random function as its first argument.
For convenience sake, sumtin exports a function as the default value. This function will return an object that contains the random generation functions. These functions have the random function bound as the first argument.
const assert = require('assert')
const {pick} = require('sumtin')(() => 0)
assert.equal(pick([1,2,3]), 1)
The pick function will always return the first value because the "random" function will always return 0. This will result in the item located at index 0 to be returned. You wouldn't do this normally.
We could also pass the Math.random function. You could pass in any function
that returns a number between and including 0 and 1. Maybe you want to
reproduce the same "random" values. You can instead pass in your favorite
psuedorandom function. Maybe the
seed-random's function.
something(rand)Picks a random function and returns a random value from that function
boolean(rand)Returns true whenever the rand function returns a value lower than or equal to 0.5. Otherwise returns false
char(rand)Generate a random char. It uses the Javascript String.fromCodePoint() to
achieve this.
date(rand)Creates a date between the Javascript minimum and maximum allowed dates.
The earliest date being -271821-04-20T00:00:00.000Z
The latest date being +275760-09-13T00:00:00.000Z
digit(rand)A numeric digit which is a number between 0 and 9
falsy(rand)This will return one of the following values:
null, undefined, false, 0, '' and NaN.
You can read more about javascript falsy values over at Mozilla's falsy documentation
futureDate(rand)A future date returns a date that has occurred after the now date. The now date is created when the module is evaluated. As a result a future can become a date from the past if the lifecycle of the application increases.
hexadecimalDigit(rand)TBD
hexColor(rand)TBD
integer(rand)Return a whole number between and including the numbers 9007199254740991 and
-9007199254740991
letter(rand)TBD
letters(rand, length = () => 20)TBD
negativeInteger(rand)Return a whole number between and including the numbers -1 and -9007199254740991
negativeNumber(rand)TBD
number(rand)TBD
pastDate(rand)TBD
pick(rand, items = [])TBD
positiveInteger(rand)Return a whole number between and including the numbers 1 and 9007199254740991
positiveNumber(rand)Return a number between and including the numbers 1 and 9007199254740991
rangedDate(rand, range = [new Date(-1), new Date(1)])TBD
rangedInteger(rand, range)Returns a integer between the range. The max value is never returned. Under the hood it will retry getting a value if the value equals the max value
rangedNumber(rand, range = [-1, 1])TBD
sometimes(rand, doFn = v => v, value, ratio = 0.5)Performs a function whenever the random value is greater than the ratio argument.
This is used both internally and could be used to apply functions "sometimes"
Something relies on tests to prove that randomly generated values are indeed random enough but not so random that it's useless. The goal is to keep test coverage at 100%.
You can run the tests yourself with npm t
----------------------------|----------|----------|----------|----------|-------------------|
File | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s |
----------------------------|----------|----------|----------|----------|-------------------|
All files | 100 | 100 | 100 | 100 | |
lib | 100 | 100 | 100 | 100 | |
helpers.js | 100 | 100 | 100 | 100 | |
helpers.spec.js | 100 | 100 | 100 | 100 | |
index.js | 100 | 100 | 100 | 100 | |
index.spec.js | 100 | 100 | 100 | 100 | |
lib/function | 100 | 100 | 100 | 100 | |
boolean.js | 100 | 100 | 100 | 100 | |
boolean.spec.js | 100 | 100 | 100 | 100 | |
char.js | 100 | 100 | 100 | 100 | |
char.spec.js | 100 | 100 | 100 | 100 | |
date.js | 100 | 100 | 100 | 100 | |
date.spec.js | 100 | 100 | 100 | 100 | |
digit.js | 100 | 100 | 100 | 100 | |
digit.spec.js | 100 | 100 | 100 | 100 | |
falsy.js | 100 | 100 | 100 | 100 | |
falsy.spec.js | 100 | 100 | 100 | 100 | |
future-date.js | 100 | 100 | 100 | 100 | |
future-date.spec.js | 100 | 100 | 100 | 100 | |
hex-color.js | 100 | 100 | 100 | 100 | |
hex-color.spec.js | 100 | 100 | 100 | 100 | |
hexadecimal-digit.js | 100 | 100 | 100 | 100 | |
hexadecimal-digit.spec.js | 100 | 100 | 100 | 100 | |
integer.js | 100 | 100 | 100 | 100 | |
integer.spec.js | 100 | 100 | 100 | 100 | |
letter.js | 100 | 100 | 100 | 100 | |
letter.spec.js | 100 | 100 | 100 | 100 | |
letters.js | 100 | 100 | 100 | 100 | |
letters.spec.js | 100 | 100 | 100 | 100 | |
negative-integer.js | 100 | 100 | 100 | 100 | |
negative-integer.spec.js | 100 | 100 | 100 | 100 | |
negative-number.js | 100 | 100 | 100 | 100 | |
negative-number.spec.js | 100 | 100 | 100 | 100 | |
number.js | 100 | 100 | 100 | 100 | |
number.spec.js | 100 | 100 | 100 | 100 | |
past-date.js | 100 | 100 | 100 | 100 | |
past-date.spec.js | 100 | 100 | 100 | 100 | |
pick.js | 100 | 100 | 100 | 100 | |
pick.spec.js | 100 | 100 | 100 | 100 | |
positive-integer.js | 100 | 100 | 100 | 100 | |
positive-integer.spec.js | 100 | 100 | 100 | 100 | |
positive-number.js | 100 | 100 | 100 | 100 | |
positive-number.spec.js | 100 | 100 | 100 | 100 | |
ranged-date.js | 100 | 100 | 100 | 100 | |
ranged-date.spec.js | 100 | 100 | 100 | 100 | |
ranged-integer.js | 100 | 100 | 100 | 100 | |
ranged-integer.spec.js | 100 | 100 | 100 | 100 | |
ranged-number.js | 100 | 100 | 100 | 100 | |
ranged-number.spec.js | 100 | 100 | 100 | 100 | |
sometimes.js | 100 | 100 | 100 | 100 | |
sometimes.spec.js | 100 | 100 | 100 | 100 | |
----------------------------|----------|----------|----------|----------|-------------------|
The following node versions are supported.
Most of these versions are supported thanks to babel transpile.
FAQs
Referentially tranparent random generation functions
We found that sumtin demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 1 open source maintainer collaborating on the project.
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