megaFilterExample.js

export class PriceSpecification {
  /**
   * @param {min: Number, max: Number} price
   */
  constructor(price) {
    this.min = price.min
    this.max = price.max
  }

  /**
   * Spec Description
   * @param {Product} product
   */
  isSatisfied(product) {
    const product_price = product.price / 100
    return product_price <= this.max && product_price >= this.min
  }
}


export class ColorSpecification {
  
  /**
   * @param color: String
   */
  constructor(color) {
    this.color = color
  }

 /**
  * Spec Description
  * @param {Product} product
 */
 isSatisfied(product) {
   // check is product have color here..
   let colorFound = false
   // Color is index "0"
   const colors = product.options[0].values 
  
   if(colors.indexOf(this.color) !== -1) colorFound = true

   return colorFound
 }}



/**
 * 'And' specification example blue 'AND' small will only satifisy,
 * this is used as a relationship between two specification blocks.
 */
export class AndSpecification {
  /** 
   * @param  {Specs} specs 
   */
  constructor(...specs) {
    this.specs = specs
  }

  isSatisfied(product) {
    return this.specs.every((spec) => spec.isSatisfied(product))
  }
}


/**
 * 'OR' specification example blue 'OR' white will satifisy, this
 * is used as a relationship between filter values in a specific specification.
 */
export class OrSpecification {
  /** 
   * @param  {Specs} specs 
   */
  constructor(...specs) {
    this.specs = specs
  }

  isSatisfied(product) {
    return this.specs.some((spec) => spec.isSatisfied(product))
  }
}


export class MegaFilter {
  /**
   * @param {Product} products 
   * @param {Spec} spec 
   */
  filter(products, spec) {
    return products.filter((product) => spec.isSatisfied(product))
  }
}


//**********
// USE CASE
//**********

const filterProducts = () => {
  // Create Mega Filter
  const megaFilter = new MegaFilter()

  // Create Price Specificaiton
  const priceParams = { min: 0, max: 40}
  const price_spec =  new PriceSpecification(priceParams)
      
  // Create Color Specifications
  const color_spec = ['blue','red'].map((value) => new ColorSpecification(value))

  // Group Specs
  const colorOptions = new OrSpecification(...color_spec)   
  // Note: This will effectively create a filter that finds products that has atlease one of the colors AND
  // is within the price limitations expressed in the price filter. 
  const finalSpec = new AndSpecification(price_spec, colorOptions)

  // Filter products ** this.products would be your products array **
  const filteredProducts = megaFilter.filter(this.products, finalSpec)
      
}