Spoeck

Specification pattern library written in typescript.

Create a specification :

import { createSpec } from 'spoeck';

const dragon = {
  color: 'blue',
  element: 'ice',
  age: 1000,
};

const dragonIsBlue = createSpec({
  name: 'dragonIsBlue',
  desc: 'Dragon is blue',
  isSatisfiedBy: (dragon: Dragon) => dragon.color === 'blue'
});

const result = dragonIsBlue.isSatisfiedBy(dragon);

const result.value // => true

Result format :

The specification isSatisifiedBy function will always return an object with these properties.

• name: Is the name of the specification.
• desc: Is the description of the specification.
• value: Is the boolean that indicate if the specification is respected.
• details: Is the list of all sub specifications results.

// With a simple rule :
const result ={
  name: 'dragonIsBlue',
  desc: 'Dragon is blue',
  value: true,
  details: [
    { name: 'dragonIsBlue', desc: 'Dragon is blue', value: true },
  ],
};

// With a composite rule :
 const dragonIsBlueIceYoung = dragonIsBlue
  .and(dragonIsIce, 'dragonIsBlueIce')
  .and(dragonIsYoung, 'dragonIsBlueIceYoung');

const compositeRuleResult = {
  name: 'dragonIsBlueIceYoung',
  desc: 'Dragon is blue AND (Dragon is ice) AND (NOT (Dragon is old))',
  value: false,
  details: [
    { name: 'dragonIsBlue', desc: 'Dragon is blue', value: true },
    { name: 'dragonIsIce', desc: 'Dragon is ice', value: true },
    { name: 'dragonIsYoung', desc: 'NOT (Dragon is old)', value: false },
  ],
}

Combining specifications with operator :

AND operator:

import { createSpec } from 'spoeck';

const dragon = {
  color: 'blue',
  element: 'ice',
  age: 1000,
};

const dragonIsBlue = createSpec({
  name: 'dragonIsBlue',
  desc: 'Dragon is blue',
  isSatisfiedBy: (dragon: Dragon) => entity.color === 'blue'
});

const dragonIsIce = createSpec({
  name: 'dragonIsIce',
  desc: 'Dragon is ice',
  isSatisfiedBy: (dragon: Dragon) => entity.element === 'ice'
});

const dragonIsBlueANDIce = dragonIsBlue.and(dragonIsIce, 'dragonIsBlueANDIce');

const result = dragonIsBlueANDIce.isSatisfiedBy(dragon);

result.value; // => true

OR operator :

const dragonIsBlueORIce = dragonIsBlue.or(dragonIsIce, 'dragonIsBlueORIce');

const result = dragonIsBlueORIce.isSatisfiedBy(dragon);

result.value; // => true

XOR operator :

const dragonIsBlueXORIce = dragonIsBlue.xor(dragonIsIce, 'dragonIsBlueXORIce');

const result = dragonIsBlueXORIce.isSatisfiedBy(dragon);

result.value; // => false

NOT operator :

const dragonIsBlueAndNotIce = dragonIsBlue.and(dragonIsIce.not('dragonIsNotIce'), 'dragonIsBlueAndNotIce');

const result = dragonIsBlueAndNotIce.isSatisfiedBy(dragon);

result.value; // => false