Package Exports

@csvenke/compose-rules

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Readme

@csvenke/compose-rules

Simple helper functions for writing composable business rules

Install

Using yarn

yarn add @csvenke/compose-rules

Using npm

npm install --save @csvenke/compose-rules

Usage

Try it out online with replit

import { and } from "@csvenke/compose-rules";

const isNumber = n => typeof n === "number";
const isLargerThanOne = n => n > 1;
const isLessThanTen = n => n < 10;

const isValidValue = and(isNumber, isLargerThanOne, isLessThanTen);

console.log(isValidValue(4)); // true
console.log(isValidValue(14)); // false

API

and

Returns a rule function that returns true if all rules are true.

Example

import { and } from "@csvenke/compose-rules";

const isLargerThanOne = n => n > 1;
const isLessThanTen = n => n < 10;

const hasValidValue = and(isLargerThanOne, isLessThanTen);

console.log(hasValidValue(11)); // false
console.log(hasValidValue(5)); // true

or

Returns a rule function that returns true if some rules are true.

Example

import { or } from "@csvenke/compose-rules";

const isNamedJohn = name => name === "John";
const isNamedJane = name => name === "Jane";

const hasValidName = or(isNamedJohn, isNamedJane);

console.log(hasValidName("Bill")); // false
console.log(hasValidName("Jane")); // true

not

Returns a rule function that returns true if all rules are false.

Example

import { not } from "@csvenke/compose-rules";

const isNamedJohn = name => name === "John";
const isNamedJane = name => name === "Jane";

const hasValidName = not(isNamedJohn, isNamedJane);

console.log(hasValidName("Bill")); // true
console.log(hasValidName("Jane")); // false
console.log(hasValidName("John")); // false

Development

Installing dependencies

yarn install

Building project

yarn build

Running tests

yarn test

Contributing

In lieu of a formal styleguide, take care to maintain the existing coding style.

License

MIT