javascript - 如何使按选项排序的方法具有通用性？

Question

我为选项“filterProductBy(options)”写了一个排序方法，告诉我如何使这个方法通用，不管参数有多少，我都可以应用这个过滤器。请告诉我该怎么做？

class Product {
    constructor(name, count, price) {
        this.name = name;
        this.count = count;
        this.price = price;
    }
}
//Сlass where products are recorded
class Shop {
    constructor(products) {
        this.products = [];
    }

    //method for adding a product
    addProduct(newProduct) {
        this.products.push(newProduct);
    }

    //method for filtering products by specified parameters
    filterProductBy(options) {
        const optionName = options.name,
            optionCount = options.count,
            optionPrice = options.price;

        const filters = {
            byName: optionName == undefined ? () => undefined :
                (actualName, optionName) => actualName === optionName,

            byCount: optionCount == undefined ? () => undefined :
                new Function("actualName, optionName", "return actualName " + optionCount),

            byPrice: optionPrice == undefined ? () => undefined :
                new Function("actualName, optionName", "return actualName " + optionPrice)
        };
        return this.products.filter(
            (product) => filters.byName(product.name, optionName)
            || filters.byCount(product.count, optionCount)
            || filters.byPrice(product.price, optionPrice));
    }
}
const shop = new Shop();
shop.addProduct(new Product("product 1", 1, 2000));
shop.addProduct(new Product("item 2", 2, 100));
shop.addProduct(new Product("some 3", 30, 300));
console.log(shop.filterProductBy({
    name: "product 1",
    count: ">=4",
    price: ">500"
}));

Answer 1

它几乎不需要那么复杂。只需遍历您获得的对象的属性，并包含一个项目(如果它与其中任何一个匹配)(因为您的过滤器是“OR”过滤器):

filterProductBy(options) {
    var keys = Object.keys(options);
    return this.products.filter(product => keys.some(key => product[key] == options[key]));
}

如果 == 不适用于所有选项，您可以在 key 上使用 switch(在 一些回调)来选择正确的关系来使用。

实例:

var products = [
  {name: "Widget", count: 12, price: 100},
  {name: "Gadget", count: 2, price: 70},
  {name: "Thingy", count: 14, price: 80}
];

function filterProductBy(options) {
    var keys = Object.keys(options);
    return this.products.filter(product => keys.some(key => product[key] == options[key]));
}

console.log("name: Widget", filterProductBy({name: "Widget"}));
console.log("name: Widget, count: 2", filterProductBy({name: "Widget", count: 2}));

获取 options 的键作为一个数组，然后在 filter 回调中使用这些键，通过使用 some 查看产品是否与它们中的任何一个匹配.

如果您想要一个“AND”过滤器，您可以使用 every而不是一些:

filterProductBy(options) {
    var keys = Object.keys(options);
    return this.products.filter(product => keys.every(key => product[key] == options[key]));
}

实例:

var products = [
  {name: "Widget", count: 12, price: 100},
  {name: "Gadget", count: 2, price: 70},
  {name: "Thingy", count: 14, price: 80}
];

function filterProductBy(options) {
    var keys = Object.keys(options);
    return this.products.filter(product => keys.every(key => product[key] == options[key]));
}

console.log("name: Widget", filterProductBy({name: "Widget"}));
console.log("name: Widget, count: 14", filterProductBy({name: "Widget", count: 14}));
console.log("name: Thingy, count: 14", filterProductBy({name: "Thingy", count: 14}));