遍历Typescript

如何解决遍历Typescript

我有一个对象，该对象具有通过lodash groupBy函数映射的分组数据， 遍历集合并检索以下信息的最佳方法是什么：

• totalProductNumber，
• totalProductSum = Sum（productsNumberInGroup * 价格）
• productsNumberPerGroup

所以输出可能是

let result = {
totalProductNumber: 8,totalProductSum: 17,productsNumberPerGroup: [{1:2},{2:3},{3:3}] // or sth. like this
}

interface IProduct {
  name: string;
  color: string;
  price: string;
 id: number
 }

    const products = {
  "1": [{
      "name": "Jim","color": "blue","price": 1,"id": 1
    },{
      "name": "Jim","id": 1
    }
  ],"2": [{
      "name": "Eddie","color": "green","price": 2,"id": 2
    },{
      "name": "Eddie","id": 2
    }
  ],"3": [{
      "name": "Ela","color": "pink","price": 3,"id": 3
    },{
      "name": "Ela","id": 3
    }
  ]
}

我的假设是使用Object.entries或Object.values

  let totalSum: number;
  let totalPrices: number[];
Object.values(products)
      .map((prod) => {
        (prod as IProduct[]).map((p) => {
            this.totalPrices.push(Number(p.price)); // here getting Cannot read property 'push' of undefined
        });
      });

解决方法

您应该进行两项更改

let totalPrices: number[];

到

let totalPrices: number[] = [];

界面的另一个变化

interface IProduct {
  name: string;
  color: string;
  price: string;
  id: number
}

更改

price: string;

到

price: number;

,

具有可变风格

interface IProduct {
  name: string
  color: string
  price: number
  id: number
}

type Products = Record<string,IProduct[]>

const products: Products = { ... }

let totalProductNumber = 0
let totalProductSum = 0
let productsNumberPerGroup: [string,number][] = []

Object.entries(products).map(([grpId,grpProducts]) => {
  totalProductNumber = totalProductNumber + grpProducts.length
  totalProductSum = totalProductSum + grpProducts.reduce((acc,curr) => acc + curr.price,0)
  productsNumberPerGroup = [...productsNumberPerGroup,[grpId,grpProducts.length]]
})

console.log(totalProductNumber) // 8
console.log(totalProductSum) // 17
console.log(productsNumberPerGroup) //[ [ '1',2 ],[ '2',3 ],[ '3',3 ] ]

风格不变

type Result = [
  totalProductNumber: number,totalProductSum: number,productsNumberPerGroup: [string,number][]
]
const initial: Result = [0,[]]

const [totalNum,totalSum,prdPerGrp] = Object.entries(products).reduce<Result>(
  ([num,sum,perGrp],grpProducts]) => {
    return [
      num + grpProducts.length,sum + grpProducts.reduce((acc,0),[...perGrp,grpProducts.length]]
    ]
  },initial
)

console.log(totalNum) // 8
console.log(totalSum) // 17
console.log(prdPerGrp) // [ [ '1',3 ] ]