javascript - 获取一系列连接的项目

Question

我有一个类别数组，如:

0: {_id: 1, image: "/static/categories/apartment.png", name: "apartments", properties: Array(2), rootCategoryId: null, …}
1: {_id: 2, image: "/static/categories/car.png", name: "cars", properties: Array(1), rootCategoryId: null, …}
2: {_id: 3, image: "/static/categories/dress.png", name: "cloathes", properties: Array(1), rootCategoryId: null, …}
3: {_id: 4, image: "/static/categories/fridge.png", name: "electronicsAndGadgets", properties: Array(1), rootCategoryId: null, …}
4: {_id: 99, image: "/static/categories/phone.png", name: "smartPhones", properties: Array(0), rootCategoryId: 4, …}
5: {_id: 100, image: "/static/categories/shoes.png", name: "shoes", properties: Array(0), rootCategoryId: 3, …}
6: {_id: 1000, image: null, name: "sneakers", properties: Array(0), rootCategoryId: 100, …}
7: {_id: 1001, image: null, name: "sandals", properties: Array(0), rootCategoryId: 100, …}

换句话说。

Root category (image: '../png', rootCategoryId: null)

Sub categories (image: '../png' OR null, rootCategoryId: ID)


1 (root) -> 100 (sub1) -> 1000 (sub2)

由于根总有图片，有时子类没有图片，我想逆向搜索直到找到图片。创建此函数以获取相关类别，但我认为它可以做得更好:

    export const getCategoryImageByByCategoryId = id => {
      if (!store) return null;
      const getCategory = (id) => _.find(categoriesList, category => category._id === id);
      const state = store.getState();
      const categoriesList = state.categories.categoriestList;
      let currentCategory = getCategory(id);
      const result = [currentCategory];
      while (currentCategory !== null) {
        const nextId = currentCategory.rootCategoryId;
        if (!nextId) {
          currentCategory = null;
        } else {
          currentCategory = getCategory(nextId);
          result.push(currentCategory);
        }
      }
      return result;
    };

最好的方法是什么？应该使用 reduce fn 吗？

Answer 1

您可以创建一个以 _id 为键的对象并调用该函数，直到获得图像。

function getCategoryImageByByCategoryId(id) {
    return reference[id].image
        || getCategoryImageByByCategoryId(reference[id].rootCategoryId);
}

var data = [{ _id: 1, image: "/static/categories/apartment.png", name: "apartments", properties: [], rootCategoryId: null }, { _id: 2, image: "/static/categories/car.png", name: "cars", properties: [], rootCategoryId: null }, { _id: 3, image: "/static/categories/dress.png", name: "cloathes", properties: [], rootCategoryId: null }, { _id: 4, image: "/static/categories/fridge.png", name: "electronicsAndGadgets", properties: [], rootCategoryId: null }, { _id: 99, image: "/static/categories/phone.png", name: "smartPhones", properties: [], rootCategoryId: 4 }, { _id: 100, image: null, name: "shoes", properties: [], rootCategoryId: 3 }, { _id: 1000, image: null, name: "sneakers", properties: [], rootCategoryId: 100 }, { _id: 1001, image: null, name: "sandals", properties: [], rootCategoryId: 100 }],
    reference = data.reduce((r, o) => {
        r[o._id] = o;
        return r;
    }, {});

console.log(getCategoryImageByByCategoryId(1000));