Condition

The Condition class represents a boolean match and/or a transformation of the input values.

import { Condition } from 'pattahn/core';

You can subclass Condition by defining a constructor (which passes the name to super) and an exec method which takes at least one argument and returns null or an array of results. Here's the simplest Condition: the identity condition.

class Id extends Condition {
  constructor() {
    super('Id');
  }
  exec(...args) {
    return args;
  }
}
module.exports = Id.factory;
const result = Id.factory().exec(7);
expect(result).toEqual([7]);
// The class is also exposed as a property of the factory
expect(Id.factory.class).toBe(Id);

There's a .factory getter on Condition that simply allows the class to be constructed without new. All first-party conditions export the factory to clean up the consuming code.