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pattahn

API Documentation

Intro

This library allows dynamic pattern matching on any values, with convenient syntax for primitives, and powerful composition of condition types when you need the extra power.

Install

npm install --save pattahn

or

yarn add pattahn

Usage

When you require/import 'pattahn' you get the main "match" function. Deep imports are used to access other APIs.

import match from 'pattahn';
import Eq from 'pattahn/cond/Eq';
import Test from 'pattahn/cond/Test';

const matcher = match()
  .with(Eq('foo').or(Eq('bar')), (value) => 'eq foo/bar')
  .with(
    Test((v) => v.length === 0),
    'empty',
  )
  .any((other) => 'other: ' + other);

matcher.exec('foo'); // => 'eq foo/bar'
matcher.exec(''); // => 'empty'
matcher.exec('baz'); // => 'other: baz'

You can also match directly by using an object. Conditions can be used with the ES6 dynamic key syntax.

import match from 'pattahn';

const result = match('foo', {
  foo: 'eq foo',
  [Eq('bar').or(Eq('baz'))]: 'foo or baz',
  _: 'default',
});

result; // => 'eq foo'

See the API Documentation for more details.